Reactive compensation controller and method for distributed photovoltaic system

Abstract

The embodiment of the invention provides a reactive compensation controller and method for a distributed photovoltaic system. The controller comprises a signal acquisition module, a metering module and a digital controller. Wherein the output end of the signal acquisition module is connected with the input end of the metering module, and the signal acquisition module is used for acquiring power grid parameters in real time. The metering module receives data from the signal acquisition module and calculates a target parameter set according to the power grid parameters. The metering module transmits the target parameter set to the digital controller. And the digital controller is responsible for evaluating the current reactive vacancy of the power grid according to the received target parameter set. Meanwhile, the reactive power vacancy, the power factor and other related parameters of the power grid are comprehensively considered, and a reactive power compensation strategy is generated. The strategy can guide how to carry out the switching operation of the capacitor. According to the embodiment of the invention, the switching strategy of the capacitor can be dynamically adjusted, the problems of abnormal switching and low system power factor are effectively solved, and the overall operation efficiency of a power grid is improved.

Description

Technical Field

[0001] The embodiments of the present application relate to but are not limited to the technical field of photovoltaic systems, and in particular to a reactive power compensation controller and method for distributed photovoltaic systems. Background Art

[0002] With the popularity of photovoltaic power generation, reactive power compensation after the photovoltaic system is connected to the grid has become a key technology. Reactive power compensation is a common practice in power systems, which aims to adjust the reactive power in the grid by adding or removing reactive compensation devices such as capacitors, thereby optimizing the power factor and reducing line losses. Due to its intermittent and uncertain nature, photovoltaic systems often have an impact on the grid, resulting in reactive power shortages and low power factor. Traditional reactive power compensation controllers may not be able to respond to these changes accurately and quickly when facing photovoltaic systems, resulting in abnormal switching and increased line losses, which in turn affects the stability and efficiency of the grid. Summary of the invention

[0003] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0004] The embodiment of the present application provides a reactive power compensation controller for a distributed photovoltaic system, which effectively solves the problems of abnormal switching and low system power factor, and improves the overall operation efficiency of the power grid.

[0005] In a first aspect, an embodiment of the present application provides a reactive power compensation controller for a distributed photovoltaic system, comprising:

[0006] Signal acquisition module, metering module, digital controller;

[0007] The output end of the signal acquisition module is connected to the input end of the metering module, and the signal acquisition module is used to collect power grid parameters, and the power grid parameters include voltage and current;

[0008] The output end of the metering module is connected to the digital controller, and the metering module is used to calculate the target parameter set according to the power grid parameters;

[0009] The digital controller is used to evaluate the reactive power shortage of the power grid according to the target parameter set, and generate a reactive power compensation strategy according to the reactive power shortage, the power factor and the power grid parameters, wherein the reactive power compensation strategy is used to instruct the switching of capacitors in the power grid.

[0010] In combination with the first aspect, in a possible implementation of the first aspect, a voltage transformer, a current transformer and a sampling circuit are provided in the signal acquisition module, and the sampling circuit is connected to the voltage transformer and the current transformer respectively; the voltage transformer is used to convert the collected voltage into a voltage signal, the current transformer is used to convert the collected current into a current signal, and the sampling circuit is used to convert the voltage signal and the current signal into digital signals.

[0011] In combination with the first aspect, in a possible implementation of the first aspect, a fault diagnosis and repair module is provided in the digital controller, and the fault diagnosis and repair module is used to monitor power grid faults, and when a power grid fault is detected, the capacitor is cut off.

[0012] In combination with the first aspect, in a possible implementation of the first aspect, the digital controller is provided with a communication module, and the communication module is used to communicate with a host computer.

[0013] In combination with the first aspect, in a possible implementation of the first aspect, the reactive power compensation controller includes a zero-crossing trigger module and a switching module, the zero-crossing trigger module is respectively connected to the digital controller and the switching module, and the zero-crossing trigger module is used to control the conduction of the switching module according to the reactive power compensation strategy, thereby controlling the switching on of the capacitor.

[0014] In combination with the first aspect, in a possible implementation manner of the first aspect, the zero-crossing trigger module is further used to control the switching module to be turned off according to the reactive compensation strategy, thereby controlling the removal of the capacitor.

[0015] In combination with the first aspect, in a possible implementation of the first aspect, the reactive power compensation controller further includes a data storage module connected to the digital controller, and the data storage module is used to store grid operation parameters and capacitor switching status information.

[0016] In combination with the first aspect, in a possible implementation of the first aspect, the reactive power compensation controller also includes a human-machine interface module, the human-machine interface module includes a key input module and a liquid crystal display module, the output end of the key input module is connected to the input end of the digital controller, and the key input module is used to complete the control parameter modification through communication with the digital controller; the input end of the liquid crystal display module is connected to the output end of the digital controller, and is used to display the current grid parameters and the switching status of the capacitor.

[0017] In a second aspect, an embodiment of the present application provides a reactive power compensation method for a distributed photovoltaic system, comprising: obtaining grid parameters, the grid parameters including voltage and current; calculating a target parameter set of the grid based on the grid parameters; evaluating the reactive power shortage of the grid based on the target parameter set, and generating a reactive power compensation strategy based on the reactive power shortage, the target parameter set and the grid parameters; and putting capacitor groups into or out of the grid according to the reactive power compensation strategy.

[0018] In combination with the second aspect, in a possible implementation of the second aspect, calculating the target parameter set of the power grid based on the power grid parameters includes: converting the power grid parameters into digital signals; adjusting the phase of the digital signal, and calculating the target parameter set of the power grid based on the adjusted digital signal.

[0019] A reactive power compensation controller for a distributed photovoltaic system provided in an embodiment of the present application comprises a signal acquisition module, a metering module and a digital controller. Among them, the output end of the signal acquisition module is connected to the input end of the metering module for real-time acquisition of grid parameters, which mainly include voltage and current. The metering module receives data from the signal acquisition module and calculates a target parameter set based on these grid parameters. Subsequently, the metering module transmits the target parameter set to the digital controller. The digital controller is responsible for evaluating the current reactive power shortage of the grid according to the received target parameter set. At the same time, it also comprehensively considers the reactive power shortage, power factor and other relevant parameters of the grid to generate a reactive power compensation strategy. This strategy can guide when and how to switch capacitors in the grid. The reactive power compensation controller provided in the embodiment of the present application enables the controller to quickly and accurately evaluate the reactive power demand of the grid through real-time data acquisition of the signal acquisition module and precise calculation of the metering module. Compared with the traditional controller, this embodiment achieves a significant improvement in response speed and adjustment accuracy, and effectively copes with the problems of reactive power shortage and low power factor caused by intermittency and uncertainty in the photovoltaic system. The digital controller can dynamically adjust the capacitor switching strategy according to the actual operation status of the power grid, thereby optimizing the power factor and improving the power quality of the power grid. This improvement not only significantly reduces line losses, but also further improves the overall operation efficiency of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is an overall module structure diagram of a reactive power compensation controller for a distributed photovoltaic system provided in an embodiment of the present application;

[0021] Figure 2 is a voltage sampling circuit diagram provided in an embodiment of the present application;

[0022] Figure 3 is a current sampling circuit diagram provided in an embodiment of the present application;

[0023] Figure 4 is a zero-crossing trigger circuit diagram of a bidirectional thyristor provided in an embodiment of the present application;

[0024] Figure 5 It is a flowchart of a reactive power compensation method provided in an embodiment of the present application;

[0025] Figure numerals: signal acquisition module 110; voltage transformer 111; current transformer 112; sampling circuit 113; metering module 120; digital controller 130; zero-crossing trigger module 140; switching switch module 150; communication module 160; data storage module 170; power module 180; clock chip 190; human-machine interface module 210; human-machine interface 211; key input module 212; liquid crystal display module 213. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0027] It should be noted that, although the logical order is shown in the flowchart, in some cases, the steps shown or described can be performed in a different order from that in the flowchart. The terms "first", "second", etc. in the specification, claims and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions that the present invention can be implemented, so they have no technical substantive significance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope of the technical content disclosed by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of narration, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of the relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0029] In the power system, the management of reactive power is crucial to maintaining the stability and efficiency of the power grid. Reactive power compensation is a common practice in the power system, which aims to adjust the reactive power in the power grid by adding or removing reactive compensation devices such as capacitors, thereby optimizing the power factor, reducing line losses, and improving the overall power supply quality of the power grid. With the rapid development of renewable energy, especially the widespread application of photovoltaic systems, the reactive power demand of the power grid has become more complex and changeable. Due to its intermittent and uncertain nature, photovoltaic systems often have an impact on the power grid, resulting in problems such as reactive power shortage and low power factor. When facing photovoltaic systems, traditional reactive compensation controllers may not be able to respond to these changes accurately and quickly, resulting in abnormal switching and increased line losses, which in turn affects the stability and efficiency of the power grid.

[0030] In view of this, the embodiment of the present application provides a reactive power compensation controller and reactive power compensation method for a distributed photovoltaic system, and the reactive power compensation controller includes a signal acquisition module, a metering module and a digital controller. Among them, the output end of the signal acquisition module is connected to the input end of the metering module for real-time acquisition of power grid parameters, which mainly include voltage and current. The metering module receives data from the signal acquisition module and calculates a target parameter set based on these power grid parameters. Subsequently, the metering module transmits the target parameter set to the digital controller. The digital controller is responsible for evaluating the current reactive power shortage of the power grid according to the received target parameter set. At the same time, it also comprehensively considers the reactive power shortage, power factor and other relevant parameters of the power grid to generate a reactive power compensation strategy. This strategy can guide when and how to switch capacitors in the power grid. The reactive power compensation controller provided in the embodiment of the present application enables the controller to quickly and accurately evaluate the reactive power demand of the power grid through real-time data acquisition of the signal acquisition module and precise calculation of the metering module. Compared with the traditional controller, this embodiment achieves a significant improvement in response speed and adjustment accuracy, and effectively copes with the problems of reactive power shortage and low power factor caused by intermittent and uncertain photovoltaic systems. The digital controller can dynamically adjust the capacitor switching strategy according to the actual operation status of the power grid, thereby optimizing the power factor and improving the power quality of the power grid. This improvement not only significantly reduces line losses, but also further improves the overall operation efficiency of the power grid.

[0031] The embodiments of the present application are further described below in conjunction with the accompanying drawings.

[0032] See also Figure 1 , Figure 1It is an overall module structure diagram of the reactive power compensation controller for distributed photovoltaic systems provided by the embodiment of the present application. The controller has built-in advanced optimization algorithms, which can automatically identify the access of photovoltaic systems and flexibly adjust the reactive power compensation strategy according to the real-time system status. Specifically, the controller is composed of three core modules: a signal acquisition module 110, a metering module 120, and a digital controller 130. The output end of the signal acquisition module 110 is closely connected to the input end of the metering module 120, and its main responsibility is to accurately collect key parameters of the power grid, such as voltage and current. The metering module 120 receives data from the signal acquisition module 110 and uses these data to calculate the target parameter set of the power grid, providing a solid data foundation for subsequent control strategies. The digital controller 130 receives the target parameter set output by the metering module 120 and evaluates the current reactive power shortage of the power grid accordingly. At the same time, combined with the evaluation results of the power factor, power grid parameters and reactive power shortage, the digital controller 130 can intelligently generate a reactive power compensation strategy, which clearly indicates when and how to perform capacitor switching operations in the power grid. It is worth noting that due to the inherent intermittent and uncertain nature of photovoltaic systems, the power grid often faces greater power fluctuations after being connected to the photovoltaic system. The controller realizes real-time monitoring and precise control of the power grid status through the close cooperation of the signal acquisition module 110, the metering module 120 and the digital controller 130. This capability not only significantly enhances the adaptability of the power grid to the fluctuations of the photovoltaic system, but also ensures that the system can quickly and accurately identify and respond to the reactive power changes introduced by the photovoltaic system. Ultimately, this helps to effectively reduce line losses, improve the overall stability of the power grid, and provide a strong guarantee for the safe and efficient operation of distributed photovoltaic systems.

[0033] In a possible embodiment, if Figure 1 As shown in FIG. 1 , the signal acquisition module 110 integrates a voltage transformer (marked as PT) 111, a current transformer (marked as CT) 112, and a sampling circuit 113. The voltage transformer 111 and the current transformer 112 are both connected to the sampling circuit 113 to form a complete signal processing link. Among them, the voltage transformer 111 can measure the bus voltage (such as Figure 1 The Ua, Ub and Uc in the photovoltaic system can be safely and accurately converted into a standard voltage signal suitable for subsequent circuit processing, while the current transformer 112 can convert the single-phase current (such as Figure 1 Ia, Ib and Ic in the sampling point current (such as Figure 1The Id, Ie and If in the photovoltaic system are converted into standard current signals suitable for subsequent circuit processing for easy measurement and processing. The sampling circuit 113 is responsible for receiving the voltage signal and current signal from the voltage transformer 111 and the current transformer 112, and converting these analog signals (such as voltage signals and current signals) into high-precision digital signals after precise conversion and processing. These digital signals are then input into the metering module 120 for further analysis. It should be noted that in the photovoltaic system, the bus voltage refers to the voltage value collected on the bus after connecting multiple solar panels in series or in parallel. As the center of the photovoltaic system's electric energy collection and distribution, the stability and range of its voltage are crucial to the normal operation of the entire system. Single-phase current refers to the current value of a certain phase measured at the power grid assessment point. This current value can reflect the operating status of the power grid at this point. The power grid assessment point is usually located at a key location of the power grid, such as a substation, the end of a transmission line, etc. At these locations, it is necessary to monitor and assess the current, voltage and other parameters of the power grid in real time to ensure the stable operation and power supply quality of the power grid. In a photovoltaic system, the sampling point current usually refers to the current value measured at a sampling point inside the photovoltaic system (such as the input end of the inverter, the output end of the solar panel, etc.). This current value can reflect the power generation status or current transmission status of the photovoltaic system at the sampling point. The measurement of the sampling point current of the photovoltaic system plays an important role in monitoring the operating status of the photovoltaic system, evaluating the power generation efficiency, and troubleshooting. For example, by measuring the current value at the input end of the inverter, the current output by the photovoltaic panel can be understood, thereby judging the power generation efficiency of the panel; by measuring the current value at the output end of the panel, it can be judged whether the panel has problems such as faults or aging.

[0034] In a feasible embodiment, the metering module 120 can receive the digital signal from the signal acquisition module 110 and perform a series of precise digital signal processing operations on it. These operations mainly include digital high-pass filtering and phase shift filtering (or phase correction) to ensure the accuracy and reliability of the signal. Through these processing steps, the metering module 120 can calculate the required parameters, that is, the target parameter set, which covers the key information such as the effective value of voltage and current, power, frequency and phase angle. Once these parameters are calculated, the metering module 120 can store them in a special metering parameter storage for subsequent use or analysis. In addition, the module also has the ability to communicate with the digital controller 130 through a serial peripheral interface (SerialPeripheral Interface, SPI), and can pass these metering parameters to the digital controller 130 in real time and accurately to support it to perform higher-level control or decision-making operations.

[0035] In a feasible embodiment, the core component of the metering module 120 can use the ATT7022A electric energy metering chip. It is worth noting that the ATT7022A has a built-in professional digital signal processing (DSP) circuit with its 16-bit high-precision AD conversion capability, and integrates six second-order analog-to-digital conversion circuits (sigma-delta ADC), precision reference voltage circuits, and a series of digital signal processing circuits for power, energy, effective value, power factor and frequency measurement. The chip can comprehensively measure the active power, reactive power, apparent power, active energy and reactive energy of each phase and phase combination. At the same time, it can also accurately measure key parameters such as current, voltage effective value, power factor, phase angle and frequency of each phase. ATT7022A supports gain and phase correction in the full digital domain, which means that the calibration of the meter can be achieved through pure software, greatly improving the convenience and flexibility of operation. In addition, ATT7022A provides active and reactive frequency calibration outputs CF1 and CF2. These two outputs can reflect the instantaneous active and reactive power information in real time, and are convenient for direct connection to the standard meter for error correction, thereby ensuring the accuracy of the measurement results. In order to facilitate communication with an external controller (such as a digital controller 130), ATT7022A is also equipped with an SPI interface. Through this interface, the measurement parameters and calibration parameters can be efficiently and accurately transmitted to the external controller to achieve real-time data update and synchronization.

[0036] In a feasible embodiment, the voltage and current signals of the power grid can be differentially input to the voltage channel and current channel of ATT7022A (high-precision three-phase power dedicated metering chip) through the corresponding transformer. As a signal transmission technology, differential input transmits information by calculating the difference between a positive signal and a negative signal, which significantly enhances the anti-interference performance and accuracy of the signal. In the voltage and current measurement scenario of the power grid, the differential input method can effectively suppress common-mode noise and interference, thereby improving the accuracy of the measurement. Specifically, the voltage and current of the power grid are first converted by the voltage transformer 111 and the current transformer 112, respectively, and then enter the corresponding channel of ATT7022A using the differential input method. Based on these input signals, ATT7022A can accurately measure the voltage and current values ​​of the power grid, and calculate key parameters such as active power, reactive power, and power factor. In addition, in order to deal with the problem of small current measurement values ​​at the sampling point when the load is close to the photovoltaic power generation, a photovoltaic current compensation channel is specially set. It is worth noting that the current of photovoltaic power generation is volatile and unstable. When it is close to the load current, it may cause deviations in the current measurement value of the sampling point, affecting the accuracy of the measurement. The photovoltaic current compensation channel is used to compensate for the current measurement error caused by photovoltaic power generation by adding a current sampling channel (i.e., sampling circuit 113). When it is detected that the photovoltaic power generation current is close to the load current, the channel will output a compensation current, which is added to the original sampling current to ensure the accuracy of the current measurement value.

[0037] In a feasible embodiment, the voltage signal can be input into the voltage channel of ATT7022A through the voltage sampling circuit, and the current signal can be input into the current channel of ATT7022A through the current sampling circuit. Figure 2 In the voltage sampling circuit shown in FIG, after the voltage enters the circuit through the VN interface and the VP interface, the high voltage signal can be converted into a low current signal through a 1:1 current type voltage transformer (such as SPT204A) for subsequent processing. The converted current signal is input to the voltage channel of ATT7022A in a differential manner. It is worth noting that an anti-aliasing filter is added to each voltage input channel to suppress high-frequency noise and interference. Figure 3In the current sampling circuit shown, the current signal is converted by a precision current transformer 112 (such as SCT254AK). This transformer has high precision and low nonlinearity, which can ensure the accuracy of current measurement. The converted current signal is also input to the current channel of ATT7022A in a differential manner. Similarly, an anti-aliasing filter can be added to each current input channel to improve the anti-interference ability of the signal. In this way, by adopting differential input, designing photovoltaic current compensation channels and reasonable sampling input circuit design, it can be ensured that ATT7022A can accurately measure the voltage and current values ​​of the power grid, and then calculate various electric energy parameters, providing an important basis for the monitoring and control of the power system.

[0038] In a feasible embodiment, the digital controller 130 serves as a core control unit, and its main responsibility is to deeply analyze the measurement results provided by the metering module 120. Based on these detailed data, the digital controller 130 can accurately determine whether the power grid needs to perform reactive compensation operations, that is, decide whether the capacitor should be put into or removed. Specifically, the digital controller 130 will accurately evaluate the current reactive power shortage of the power grid based on the acquired target parameter set. This evaluation process not only takes into account the reactive power shortage itself, but also integrates the power factor and other key parameters of the power grid. Based on this comprehensive evaluation result, the digital controller 130 can generate a reasonable reactive power compensation strategy. The reactive power compensation strategy specifies in detail the timing and method of switching capacitors in the power grid, aiming to optimize the reactive power distribution of the power grid by accurately regulating the switching of capacitors, thereby improving the operating efficiency and stability of the power grid.

[0039] Furthermore, in order to optimize the system performance, the ATmega128L microcontroller in the AVR series can be preferably used as the main control chip of the digital controller 130. ATmega128L is a high-performance, low-power 8-bit microprocessor, and its RISC architecture ensures efficient instruction execution. The microcontroller is equipped with 53 programmable I / O ports, 2 programmable USART interfaces, 128K bytes of system programmable Flash memory and 4K bytes of EEPROM, which fully meet the needs of complex control tasks. It is worth mentioning that ATmega128L also supports on-chip debugging. Through the JTAG interface, the Flash memory, EEPROM, fuse bits and lock bits can be easily programmed and configured. This feature greatly simplifies the development process and improves debugging efficiency. In terms of communication, ATmega128L achieves efficient communication with ATT7022A through the SPI bus interface. This connection method not only ensures the accurate writing of calibration data, but also can easily read the results of the internal registers of ATT7022A, providing reliable data support for subsequent control decisions.

[0040] In a possible embodiment, if Figure 1 As shown, the reactive power compensation controller also integrates a zero-crossing trigger module 140 and a switching switch module 150, wherein the zero-crossing trigger module 140 is closely connected with the digital controller 130 and the switching switch module 150, respectively, to form an efficient control system. In this system, the zero-crossing trigger module 140 can not only accurately control the conduction of the switching switch module 150 according to the reactive power compensation strategy transmitted by the digital controller 130 to realize the input of the capacitor; at the same time, it can also control the closing of the switching switch module 150 in a timely manner according to the strategy to complete the removal of the capacitor. Through this flexible control method, the zero-crossing trigger module 140 ensures the accuracy and effectiveness of the input and removal of the capacitor, thereby realizing efficient management of the capacitor state. In this embodiment, the switching switch module 150 specifically selects a thyristor switching switch to provide more reliable switching performance. It is worth noting that since the voltage at both ends of the capacitor has the characteristic of not being able to change suddenly, when there is a large difference between the grid voltage and the capacitor voltage, directly triggering the thyristor may cause a significant current shock. In order to effectively avoid the current shock generated during the switching of capacitors, the switching operation can be performed at the moment when the voltage across the thyristor is zero. Therefore, this embodiment particularly selects a chip with a zero-crossing trigger function to control the switching of capacitors to ensure smooth and safe operation. Figure 4 , this figure is the zero-crossing trigger circuit diagram of the bidirectional thyristor. Among them, the MOC3083 thyristor is the core component, and through precise circuit design, the precise zero-crossing trigger control of the thyristor is realized. This design not only improves the accuracy of reactive power compensation control, but also further ensures the stable operation of the power system.

[0041] In a feasible embodiment, the digital controller 130 has a built-in fault diagnosis and repair module, which can monitor the operating status of the power grid in real time to quickly discover and diagnose potential faults. This design gives technicians the ability to perform efficient troubleshooting and software updates through remote access, greatly improving the convenience and efficiency of operation and maintenance. More importantly, once the module detects any fault signal in the power grid, it can immediately trigger the emergency response mechanism and quickly interrupt the switching operation of the capacitor, thereby effectively curbing the spread of the fault and ensuring that the power grid can maintain a safe and stable operating state.

[0042] In a feasible embodiment, the digital controller 130 is equipped with a communication module 160, which is designed to achieve fast and efficient information exchange with the host computer. Figure 1As shown in the figure, using RS232 / 485 serial communication technology, the module can easily transmit the operating parameters of the power grid and the real-time status data of the controller to the host computer. In addition, it also undertakes the task of exporting data stored in ferroelectric RAM (FRAM) and supports the calibration of system time to ensure data synchronization and accuracy.

[0043] Furthermore, the reactive power compensation controller also integrates a data storage module 170 which is closely connected to the digital controller 130. This module can store key operating parameters of the power grid and switching status information of the capacitor. Figure 1 As shown, in the preferred configuration, the data storage module 170 uses a 64K-bit ferroelectric memory FM24C64, which supports up to 10 12 The memory is carefully used to store the system's initial settings to ensure the accuracy of the configuration information. At the same time, it also regularly records the operating parameters of the low-voltage power grid to capture every subtle change in the grid. In addition, key information such as system fault status is also properly stored here for emergency use. These detailed historical records are not only convenient for the monitoring master station to access at any time, but also provide solid and reliable data support for in-depth analysis of the grid operation status and ensuring the stable operation of the grid.

[0044] In a possible embodiment, if Figure 1 As shown, the digital controller 130 is not only closely connected with the power module 180 to ensure a stable power supply, but also synchronized with the clock chip 190 (such as a crystal oscillator 24.576M) to ensure the accuracy and consistency of the internal time reference. This design enables the digital controller 130 to efficiently and accurately perform various control tasks, including real-time adjustment and monitoring of reactive power compensation strategies. Specifically, the power module 180 provides stable and reliable power for the digital controller 130, which can ensure that the digital controller 130 can obtain stable and compliant power input under various power grid conditions, thereby ensuring the stable performance of its performance. The connection with the clock chip 190 gives the digital controller 130 an accurate time perception capability. The clock chip 190 provides the digital controller 130 with a high-precision time signal. This enables the digital controller 130 to accurately record changes in the state of the power grid, respond to various events in a timely manner, and quickly adjust the reactive power compensation strategy when necessary to ensure the stable operation of the power grid.

[0045] In a feasible embodiment, the reactive power compensation controller of this embodiment also integrates a temperature adjustment control function. This design significantly reduces the failure rate caused by overheating of the equipment and ensures the stability and reliability of the controller during long-term operation. In addition, the controller has a maximum output circuit of up to 24 channels, which greatly improves its flexibility and adaptability in a complex power grid environment.

[0046] In a feasible embodiment, the reactive power compensation controller also integrates a human-machine interface module 210, which is composed of a human-machine interface 211, a key input module 212 and a liquid crystal display module 213, so as to realize intuitive interaction between the user and the controller. The output end of the key input module 212 is directly connected to the input end of the digital controller 130 through the human-machine interface 211, and the user can easily modify the control parameters through communication with the digital controller 130. The input end of the liquid crystal display module 231 is connected to the output end of the digital controller 130 through the human-machine interface 211, and the various parameters of the current power grid and the switching state of the capacitor are displayed in real time. Specifically, the key input module 212 is equipped with four general keys: confirm, exit, forward and backward. These keys not only allow the user to manually adjust the switching state of the capacitor, but also conveniently switch the content of the liquid crystal display and set the system clock time. Preferably, the LCD display part adopts the RT12864 module, which has rich display content, mainly covering the current current, voltage, power factor, active power, reactive power and other key parameters of each phase, and clearly displays the switching status of each capacitor and the system time, providing users with comprehensive and intuitive power grid monitoring information. When the system is abnormal, it can automatically generate a variety of alarm events and remind users through nodes or sounds. Such a design not only improves the convenience of user operation, but also provides strong support for the stable operation of the power grid.

[0047] In a feasible implementation case, in order to meet the demand for communication capabilities of modern power grids, the reactive power compensation controller of this embodiment not only complies with the RS485 hardware standard, but also fully supports the MODBUS-RTU message protocol standard. This communication function provides strong support for remote monitoring and control. Through standard communication interfaces and protocols, technicians can easily realize remote data exchange, status monitoring, and the issuance of control instructions, thereby greatly improving the efficiency and intelligence level of power grid operation and maintenance.

[0048] Optionally, the reactive power compensation controller of this embodiment can also accurately predict the reactive power demand of the power grid based on artificial intelligence algorithms and machine learning technology, and dynamically adjust the reactive power compensation strategy accordingly, thereby significantly improving the system's adaptability and response speed. Through in-depth analysis and learning of historical power grid data by machine learning algorithms, the controller can capture the changing laws of the reactive power demand of the power grid, and then accurately predict future reactive power demand. Based on these prediction results, the controller can make reasonable reactive power compensation adjustments in advance, effectively avoiding the lag and inaccuracy that may exist in traditional methods.

[0049] The reactive power compensation controller of this embodiment, its capacitor switching control strategy (i.e., reactive power compensation strategy), innovatively takes reactive power shortage as the core judgment basis, while taking into account the comprehensive consideration of power factor and voltage. The strategy first analyzes the voltage state of the power grid to ensure voltage stability; then, it deeply evaluates the reactive power status of the power grid and accurately determines the power factor. By comparing with the preset value, it decides whether to perform the capacitor switching operation and the optimal method to perform it, aiming to maximize the effective compensation of reactive power. Compared with the traditional controller, the reactive power compensation controller has significantly improved the response speed and adjustment accuracy, and effectively copes with the challenges of reactive power shortage and low power factor caused by intermittent and uncertain photovoltaic systems. In the actual application scenario, taking the 400V photovoltaic access grid system as an example, the reactive power compensation controller of this embodiment can display the system operation status in real time and intuitively with its large-screen LCD display module, which brings great convenience to the operation and maintenance personnel. Once the system detects any abnormality or fault, the controller can immediately remind the user to pay attention and take corresponding measures through various methods such as node flashing and sound alarm. This instant feedback mechanism effectively avoids potential safety hazards and ensures the stable and reliable operation of the power grid. In addition, through the RS485 communication interface, the remote monitoring center can easily realize remote switching control of the controller, real-time status monitoring, and remote parameter modification. It not only greatly improves the operation and maintenance efficiency, but also effectively reduces the operation and maintenance costs, providing solid and strong support for the intelligent management and optimization of photovoltaic systems.

[0050] In addition, the embodiment of the present application provides a reactive power compensation method, which can be applied to the reactive power compensation controller of the previous embodiment. Figure 5 As shown, the method includes but is not limited to steps 510 to 540.

[0051] Step 510: Acquire grid parameters, which include voltage and current;

[0052] Step 520: Calculate a target parameter set of the power grid according to the power grid parameters;

[0053] Step 530: Evaluate the reactive power deficit of the power grid according to the target parameter set, and generate a reactive power compensation strategy according to the reactive power deficit, the target parameter set and the power grid parameters;

[0054] Step 540: Add or remove capacitor banks in the power grid according to the reactive power compensation strategy.

[0055] In a feasible embodiment, the process of calculating the target parameter set of the power grid based on the power grid parameters specifically includes the following two key steps: first, the power grid parameters (such as voltage and current) need to be converted into digital signals for subsequent digital processing and analysis; second, the phase of the converted digital signal is adjusted to ensure the accuracy and consistency of the signal, and then based on the adjusted digital signal, professional algorithms and models are used to calculate the target parameter set of the power grid.

[0056] It should be noted that since the reactive compensation method of this embodiment can be applied to the reactive compensation controller described above, the reactive compensation method of this embodiment and the reactive compensation controller of the previous embodiment have the same technical principles and the same beneficial effects. In order to avoid repetition, they will not be repeated here.

[0057] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A reactive power compensation controller for a distributed photovoltaic system, characterized in that: include: Signal acquisition module, metering module and digital controller; The output end of the signal acquisition module is connected to the input end of the metering module, and the signal acquisition module is used to collect power grid parameters, and the power grid parameters include voltage and current; The output end of the metering module is connected to the digital controller, and the metering module is used to calculate the target parameter set according to the power grid parameters; The digital controller is used to evaluate the reactive power shortage of the power grid according to the target parameter set, and generate a reactive power compensation strategy according to the reactive power shortage, the power factor and the power grid parameters, wherein the reactive power compensation strategy is used to instruct the switching of capacitors in the power grid.

2. A reactive power compensation controller for a distributed photovoltaic system according to claim 1, characterized in that: The signal acquisition module is provided with a voltage transformer, a current transformer and a sampling circuit, and the sampling circuit is connected to the voltage transformer and the current transformer respectively; the voltage transformer is used to convert the collected voltage into a voltage signal, the current transformer is used to convert the collected current into a current signal, and the sampling circuit is used to convert the voltage signal and the current signal into digital signals.

3. A reactive power compensation controller for a distributed photovoltaic system according to claim 1, characterized in that: The digital controller is provided with a fault diagnosis and repair module, which is used to monitor power grid faults and cut off the capacitor switching when a power grid fault is detected.

4. A reactive power compensation controller for a distributed photovoltaic system according to claim 1, characterized in that: The digital controller is provided with a communication module, and the communication module is used for communicating with a host computer.

5. A reactive power compensation controller for a distributed photovoltaic system according to claim 1, characterized in that: The reactive power compensation controller comprises a zero-crossing trigger module and a switching switch module. The zero-crossing trigger module is connected to the digital controller and the switching switch module respectively. The zero-crossing trigger module is used to control the switching switch module to be turned on according to the reactive power compensation strategy, thereby controlling the switching on of the capacitor.

6. A reactive power compensation controller for a distributed photovoltaic system according to claim 5, characterized in that: The zero-crossing trigger module is also used to control the switching module to close according to the reactive power compensation strategy, thereby controlling the removal of the capacitor.

7. A reactive power compensation controller for a distributed photovoltaic system according to claim 1, characterized in that: The reactive power compensation controller further comprises a data storage module connected to the digital controller, wherein the data storage module is used to store grid operation parameters and capacitor switching state information.

8. The reactive power compensation controller for a distributed photovoltaic system according to claim 1, characterized in that: The reactive power compensation controller also includes a human-machine interface module, which includes a key input module and a liquid crystal display module. The output end of the key input module is connected to the input end of the digital controller, and the key input module is used to complete the control parameter modification through communication with the digital controller; the input end of the liquid crystal display module is connected to the output end of the digital controller, and is used to display the current power grid parameters and the switching status of the capacitor.

9. A reactive power compensation method for a distributed photovoltaic system, characterized in that: include: Acquiring grid parameters, wherein the grid parameters include voltage and current; Calculating a target parameter set of a power grid according to the power grid parameters; Evaluate the reactive power deficit of the power grid according to the target parameter set, and generate a reactive power compensation strategy according to the reactive power deficit, the target parameter set and the power grid parameters; The capacitor bank is put into operation or removed from the power grid according to the reactive power compensation strategy.

10. A reactive power compensation method for a distributed photovoltaic system according to claim 9, characterized in that: Calculating the target parameter set of the power grid according to the power grid parameters includes: converting the power grid parameters into digital signals; adjusting the phase of the digital signal, and calculating the target parameter set of the power grid according to the adjusted digital signal.

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