Source-network interaction type roof photovoltaic energy exchange control system

Abstract

A source network interaction type roof photovoltaic energy exchange control system is characterized in that a universe AIR724 chip is connected with a capacitor controller through two paths of RS-485 interfaces, the universe AIR724 chip is connected with a power supply module, a TF and key module and an Ethernet module, and the Ethernet module is connected with a network platform. According to the invention, the energy output of the photovoltaic power generation system can be dynamically adjusted according to the real-time demand of the power grid, the energy management is optimized, the power generation efficiency of the photovoltaic system is improved, and the interactivity and controllability with the power grid are enhanced. Through realizing multi-channel capacitor control, the controller can adjust the switching of the capacitor in real time according to the actual load condition of the power grid, thereby optimizing the reactive power compensation, improving the stability and efficiency of the power grid, and improving the dynamic energy management capability. By integrating an advanced communication chip and an SIM module, remote monitoring, management and operation are realized. And power supply and data storage and analysis are optimized and improved, so that the stability and traceability of the system are improved.

Description

Technical Field

[0001] The invention relates to the technical field of power electronics. Background Art

[0002] At present, photovoltaic power generation systems generally use maximum power point tracking (MPPT) technology to improve the power generation efficiency of photovoltaic cells, and use power electronic equipment to achieve grid-connected operation. However, these systems often lack interactivity with the grid and cannot perform dynamic energy management according to the real-time needs of the grid.

[0003] The current power grid monitoring equipment using a single communication interface and the power controllers with only basic data recording functions have the following disadvantages or shortcomings:

[0004] (1) Limited control capability: Existing equipment can usually only achieve basic energy exchange and cannot dynamically adjust according to the actual load conditions of the power grid;

[0005] (2) Insufficient communication capabilities: Traditional photovoltaic systems lack effective remote communication means, which limits the ability of remote monitoring and management;

[0006] (3) The power supply design is not stable enough: the existing system may have fluctuations in the power supply design, affecting the stable operation of the system;

[0007] (4) Weak data storage and analysis capabilities: Most systems lack effective data storage and traceability mechanisms, which is not conducive to troubleshooting and performance analysis;

[0008] (5) Poor real-time performance and controllability: Existing systems often cannot provide real-time monitoring and remote control, making system maintenance and scheduling inflexible and inconvenient. Summary of the invention

[0009] In order to solve the above problems existing in the existing photovoltaic energy exchange controller, the present invention provides a source-grid interactive rooftop photovoltaic energy exchange control system.

[0010] The technical solution adopted by the present invention to achieve the above-mentioned purpose is: a source-grid interactive rooftop photovoltaic energy exchange control system, the Hezhou AIR724 chip is connected to the capacitor controller through two RS-485 interfaces, the Hezhou AIR724 chip is connected to the power module, TF and key module and Ethernet module, the Ethernet module is connected to the network platform, the DC bus voltage is used as the main signal, and the battery SOC is used as the auxiliary signal. The control central management layer comprehensively integrates various information to make mode judgments, and sends control instructions to the underlying control layer when the mode changes. The functional unit converter is adjusted through the underlying control layer to achieve bus voltage stability and system power balance.

[0011] It also includes a LoRa wireless communication module, which is connected to the Hezhou AIR724 chip.

[0012] It also includes a SIM module, which connects the Hezhou AIR724 chip and the server.

[0013] The power supply module is a multi-stage step-down and voltage-stabilizing structure. It inputs 220V AC power from the mains, reduces the voltage to 12V through the step-down module, and then converts the 12V into 5V through the second-stage step-down and voltage-stabilizing module.

[0014] The source-grid interactive rooftop photovoltaic energy exchange control system of the present invention can dynamically adjust the energy output of the photovoltaic power generation system according to the real-time needs of the power grid, optimize energy management, improve the power generation efficiency of the photovoltaic system, and enhance the interactivity and controllability with the power grid. On the one hand, by realizing multi-channel capacitor control, the controller can adjust the switching of capacitors in real time according to the actual load conditions of the power grid, thereby optimizing reactive power compensation, improving the stability and efficiency of the power grid, and improving the dynamic energy management capabilities; on the other hand, it overcomes the problem of insufficient communication capabilities of existing photovoltaic systems, and realizes remote monitoring, management and operation by integrating advanced communication chips and SIM modules, ensuring effective system maintenance and updates even in remote areas. In addition, optimization and improvement have been made to power supply and data storage and analysis to improve system stability and traceability. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the source-grid interactive rooftop photovoltaic energy exchange control system of the present invention.

[0016] Figure 2 It is the RS-485 interface circuit diagram of the present invention.

[0017] Figure 3 It is the RS-485 interface circuit diagram of the present invention.

[0018] Figure 4 It is the circuit diagram of the AIR724 chip of the present invention.

[0019] Figure 5 It is the circuit diagram of the power module of the present invention.

[0020] Figure 6 It is the circuit diagram of the key module of the present invention.

[0021] Figure 7 It is the circuit diagram of the TF module of the present invention.

[0022] Figure 8 It is the circuit diagram of the SIM module of the present invention.

[0023] Fig. 9 It is the circuit diagram of the Ethernet module of the present invention.

[0024] Fig.10 This is the circuit diagram of the LoRa module of the present invention.

[0025] Fig.11 It is a coordinated control flow chart of a multi-port source-grid interactive rooftop photovoltaic energy exchange controller system. DETAILED DESCRIPTION

[0026] The source-grid interactive rooftop photovoltaic energy exchange control system of the present invention is as follows Figure 1 As shown, it mainly includes AIR724 chip, RS-485 interface, power module, TF and key module, Ethernet module and Lora module. The Hezhou AIR724 chip is connected to the capacitor controller through two RS-485 interfaces, the Hezhou AIR724 chip is connected to the power module, TF and key module and Ethernet module, and the Ethernet module is connected to the network platform.

[0027] like Figure 2 and Figure 3 As shown in the figure, the source-grid interactive rooftop photovoltaic energy exchange controller system is equipped with two RS-485 interfaces for connecting with the capacitor controller. The existence of these two interfaces enables the system to realize multi-channel capacitor control, so that the switching of capacitors can be accurately controlled according to the actual load of the power grid to achieve the effect of reactive power compensation. As an industrial standard interface, RS-485 has the advantages of strong anti-interference and long transmission distance, and is suitable for stable operation in complex power environments.

[0028] like Figure 4 As shown in the figure, the core control part of the source-network interactive rooftop photovoltaic energy exchange controller system uses the AIR724 chip, which has strong communication capabilities, especially in cellular network communication and low power consumption scenarios. As the main control chip, AIR724 is mainly responsible for the management and instruction processing of each module, and supports 4G communication functions, so that the source-network interactive rooftop photovoltaic energy exchange controller can be remotely monitored, managed and operated through the mobile network. Through this chip, the source-network interactive rooftop photovoltaic energy exchange controller system can receive update instructions issued by the platform anytime and anywhere, and feedback the working status of the system.

[0029] like Figure 5 As shown in the figure, power supply is the basis for stable operation of the system. The source-grid interactive rooftop photovoltaic energy exchange controller system adopts a multi-level buck and voltage stabilization design. First, the system receives 220V AC power from the mains, reduces the voltage to 12V through the buck module, and then converts 12V to 5V through the second-level buck and voltage stabilization module to meet the power supply requirements of each module. Such a hierarchical design can effectively avoid the impact of power supply fluctuations on the system, while ensuring the power stability of sensitive devices such as the main control chip and communication module.

[0030] As shown Figure 7 As shown in the figure, the system has built-in multiple TF card storage modules to record all operation instructions and feedback information of the source-grid interactive rooftop photovoltaic energy exchange controller. Whenever the system sends or receives a control command, it will be archived in the TF card to form a complete operation log. These data can not only help technicians troubleshoot problems, but can also be uploaded to the FTP server regularly for remote inspection and analysis. The data storage function of the TF card is an important part of the self-inspection and traceability of the entire system, which effectively improves the efficiency of fault location and maintenance.

[0031] like Figure 6 As shown in the figure, the system is designed with several physical buttons for basic functions of the source-grid interactive rooftop photovoltaic energy exchange controller, such as system reset and program burning. Figure 8 As shown in the figure, the SIM module provides remote management function for the system. Through the SIM module, the system can obtain time data and upload it to the server, or receive remote firmware update instructions through the mobile network. This not only ensures that on-site maintenance personnel can directly control it through buttons, but also realizes the convenience of remote management, especially in the environment where uninterrupted operation is required in the power system, which greatly improves the flexibility and convenience of system maintenance.

[0032] like Fig. 9 As shown in the figure, in order to ensure the real-time and controllability of the system, an Ethernet interface is also added to the design, so that the source-grid interactive rooftop photovoltaic energy exchange controller can be directly connected to the network platform. Through this interface, the system can maintain data communication with the background management platform to achieve real-time monitoring of the system's operating status. At the same time, the platform can also remotely send software update packages or adjust system configurations through Ethernet, thus avoiding the complexity of on-site operations. Through this design, power operation and maintenance personnel can grasp the working status of the system anytime and anywhere, and conduct effective remote control and scheduling.

[0033] like Fig.10 As shown in the figure, the system design also uses the LoRa wireless communication module for communication connection between the head end and the end end. LoRa technology has the characteristics of low power consumption and long-distance transmission, and is suitable for scenarios where equipment is dispersed and long-distance communication is required in the power system. Through the LoRa module, the source-grid interactive rooftop photovoltaic energy exchange controller can achieve synchronous control over a large range. Especially for reactive power compensation, the system can perform refined compensation calculations based on the data feedback from the head end and the end end to ensure that the power quality in the entire power system is maintained at a relatively ideal level.

[0034] The coordinated control method of the source-grid interactive rooftop photovoltaic energy exchange controller uses the DC bus voltage as the main signal and the battery SOC as the auxiliary signal. The central management layer of the control integrates various information to make mode judgments, and sends control instructions to the underlying control layer when the mode changes. The underlying control layer adjusts the converters of each functional unit, and finally achieves bus voltage stability and system power balance.

[0035] (I) Dispatched grid-connected operation mode (economic target)

[0036] Under the dispatched grid-connected operation mode, the system operation mode and corresponding coordinated control method are as follows:

[0037] Mode 1-1: The photovoltaic energy is particularly sufficient, the battery SOC is less than 90%, and it can be charged. The photovoltaic power generation unit is sufficient to support the inverter power and the battery charging power. At this time, one photovoltaic power generation unit is controlled by MPPT and the other is controlled by constant voltage (when the power is too large, the MPPT can be stopped as needed); the energy storage unit is controlled by constant voltage / constant current charging (determined by SOC); the bidirectional DC / AC converter is controlled by PQ. The DC bus is controlled by the photovoltaic unit and maintained at 1.0Un (rated bus voltage 720V). The system power is provided by the photovoltaic unit.

[0038] When the output power of the photovoltaic unit is less than the power required by the system, the bus voltage drops. When the drop voltage is detected to be greater than 0.05Un, the system switches from mode 1-1 to mode 1-3.

[0039] Mode 1-2: The photovoltaic energy is particularly sufficient, the battery SOC>90%, and cannot be charged, and the photovoltaic power is sufficient to support the inverter power. At this time, the photovoltaic power generation unit is MPPT controlled on one side and constant voltage controlled on the other side; the energy storage unit is on standby; the bidirectional DC / AC converter is PQ controlled. The photovoltaic unit controls the DC bus and maintains it at 1.0Un. The grid-connected power is provided by the photovoltaic unit.

[0040] When the power provided by the photovoltaic unit is less than the dispatched power, the bus voltage drops. When the drop voltage is detected to be greater than 0.05Un, the system switches from mode 1-1 to mode 1-4.

[0041] Mode 1-3: The photovoltaic energy is relatively sufficient, the battery SOC is less than 90%, and the photovoltaic power is sufficient to support the inverter power, but not enough to support the battery charging power and the inverter power. At this time, the photovoltaic power generation unit is under MPPT control and constant voltage control; the energy storage unit is on standby; the bidirectional DC / AC converter is under PQ control. The photovoltaic unit controls the DC bus and maintains it at 1.0Un. The grid-connected power is provided by the photovoltaic unit.

[0042] When the power provided by the photovoltaic unit is less than the dispatching power, the bus voltage drops. When the drop voltage is detected to be greater than 0.05Un, the system switches from mode 1-3 to mode 1-4. To ensure that the photovoltaic energy increases to enter mode 1, the system can enter mode 1-1. In mode 1-3 operation mode, the battery is charged at fixed intervals according to the SOC situation. If the bus voltage is stable at 1.0Un, it switches to mode 1-1, otherwise it returns to mode 1-3.

[0043] Mode 1-4: The photovoltaic energy is not sufficient, the battery SOC>40%, and it can be discharged. If the photovoltaic energy is insufficient, the inverter power difference can be supplemented by the battery. At this time, both photovoltaic power generation units are MPPT controlled; the energy storage unit is constant voltage discharge controlled; the bidirectional DC / AC converter is PQ controlled. The DC bus is controlled by the battery unit and maintained at 1.0Un. The grid-connected power is provided by the photovoltaic unit and the energy storage system.

[0044] When the battery is discharged to SOC≤40%, the battery stops discharging and the bus voltage drops. When the drop voltage is detected to be greater than 0.05Un, according to the superior control, if free grid connection is allowed, the system switches from mode 4 to free grid connection mode 1-5; if free grid connection is not allowed, the system switches from mode 1-4 to mode 1-6. When the photovoltaic energy is sufficient, the bus voltage rises. When the rising voltage is detected to be greater than 0.05Un, the system switches from mode 1-4 to mode 1-3.

[0045] Mode 1-5: The photovoltaic energy is not sufficient, the battery SOC is less than 40%, and it cannot be discharged. The photovoltaic power is not enough to support the inverter power, and the upper-level scheduling allows free grid connection. At this time, both photovoltaic power generation units are MPPT controlled; the energy storage unit is on standby; the bidirectional DC / AC converter is DC bus voltage controlled (limiting the maximum power to the scheduling value). The DC bus is controlled by the bidirectional DC / AC converter and maintained at 1.0Un. The grid-connected power is provided by the photovoltaic unit.

[0046] When the photovoltaic energy is sufficient and the grid-connected power reaches the limit value, the bus voltage rises. When the rising voltage is detected to be greater than 0.05Un, the system switches from mode 1-5 to mode 1-3.

[0047] Mode 1-6: The photovoltaic energy is not sufficient, the battery discharges to SOC < 40%, and no longer discharges. The photovoltaic power is not enough to support the inverter power, but it is enough to support the battery charging power, and enters mode 1-6. At this time, the photovoltaic power generation unit is MPPT controlled on one side and constant voltage controlled on the other side; the energy storage unit is constant voltage / constant current charging control; the bidirectional DC / AC converter is on standby. The photovoltaic unit controls the DC bus and maintains it at 1.0Un. The battery charging power is provided by the photovoltaic unit.

[0048] When the power provided by the photovoltaic unit is less than the charging power, the bus voltage drops. When the drop voltage is detected to be greater than 0.05Un, the system shuts down. After entering this mode, it will not exit until the battery is charged to 90%.

[0049] (II) Free grid-connected operation mode (reliability target)

[0050] In free grid-connected operation, the use of batteries is no longer introduced (energy storage unit is on standby). In this operation mode, the system operation mode and the corresponding coordinated control method are as follows:

[0051] Mode 2-1: The photovoltaic energy is relatively insufficient, and the maximum photovoltaic power generation power does not reach the maximum grid-connected power of the inverter. At this time, both photovoltaic power generation units use MPPT control, and the bidirectional DC / AC converter is controlled by the DC bus voltage. The DC bus is controlled by the bidirectional DC / AC converter and maintained at 1.0Un. The grid-connected power is provided by the photovoltaic unit. Mode 1-5 can be regarded as a special case of mode 2-1 - considering the battery SOC.

[0052] Mode 2-2: The photovoltaic energy is particularly sufficient, and the maximum photovoltaic power generation is greater than the rated power of the inverter. At this time, the photovoltaic power generation unit is MPPT controlled on one side and constant voltage controlled on the other side, and the bidirectional DC / AC converter works at rated power. The DC bus is controlled by the photovoltaic unit and maintained at 1.0Un. The grid-connected power is provided by the photovoltaic unit. Mode 2-2 is regarded as a special case of mode 1-2 and mode 1-3 - the battery SOC is not considered.

[0053] When the output power of the photovoltaic unit is greater than the rated power of the bidirectional DC / AC, the bidirectional DC / AC converter operates in current limiting mode, and the AC grid-connected power is limited to the rated value. It cannot control the bus voltage. When the rising voltage is detected to be greater than 0.05Un, the system switches from mode 2-1 to mode 2-2; when the photovoltaic power decreases and cannot support the rated power of the battery, the bus voltage drops. When the dropping voltage is detected to be greater than 0.05Un, the system switches from mode 2-2 to mode 2-1.

[0054] (III) Nighttime operation mode (power quality target)

[0055] The photovoltaic power generation unit has stopped working during night operation. In this operation mode, the system operation mode and the corresponding coordinated control method are as follows:

[0056] Mode 3: Battery SOC∈(40%, 90%), can be charged. At this time, the energy storage unit works in constant voltage / constant current charging mode according to the battery SOC, and the bidirectional DC / AC converter works in rectification mode. The DC bus is controlled by the bidirectional DC / AC converter.

[0057] When the battery is charged to SOC>90%, all devices are in standby mode.

[0058] According to the previous analysis, we can see that the system has different working modes under different operation modes, and the coordinated control methods between converters in different working modes are not consistent. Here, the coordinated control methods between converters under different operation modes and working modes are summarized, as shown in the table.

[0059] Summary table of coordinated control methods between converters in each working mode.

[0060]

[0061] The present invention is described by way of embodiments, and those skilled in the art will appreciate that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application belong to the protection scope of the present invention.

Claims

1. A source-grid interactive rooftop photovoltaic energy exchange control system, characterized by: The Hezhou AIR724 chip is connected to the capacitor controller through two RS-485 interfaces. The Hezhou AIR724 chip is connected to the power module, TF and button module and Ethernet module. The Ethernet module is connected to the network platform. The DC bus voltage is used as the main signal and the battery SOC is used as the auxiliary signal. The central management layer of the control integrates various information to make mode judgments, and sends control instructions to the underlying control layer when the mode changes. The functional unit converter is adjusted through the underlying control layer to achieve bus voltage stability and system power balance.

2. A source-grid interactive rooftop photovoltaic energy exchange control system according to claim 1, characterized in that: It also includes a LoRa wireless communication module, which is connected to the Hezhou AIR724 chip.

3. A source-grid interactive rooftop photovoltaic energy exchange control system according to claim 1, characterized in that: It also includes a SIM module, which connects the Hezhou AIR724 chip and the server.

4. A source-grid interactive rooftop photovoltaic energy exchange control system according to claim 1, characterized in that: The power supply module is a multi-stage step-down and voltage-stabilizing structure. It inputs 220V AC power from the mains, reduces the voltage to 12V through the step-down module, and then converts the 12V into 5V through the second-stage step-down and voltage-stabilizing module.

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