A static var generator device with photovoltaic power generation

Abstract

The present invention relates to the technical field of reactive power compensation of power grid lines, and more specifically, to a static reactive power generator device with photovoltaic power generation. It includes a detection module, a control module, an IGBT-IPM module, a communication module, an energy storage system and a backup power supply, a solar panel and a voltage regulating transformer. The detection module, the IGBT-IPM module and the communication module are electrically connected to the control module respectively, the regulating transformer and the energy storage system are electrically connected to the IGBT-IPM module respectively, the backup power supply and the solar panel are electrically connected to the energy storage system respectively, and the backup power supply is electrically connected to the detection module. It has simple structure, convenient installation, wireless control, remote debugging, green environmental protection, good reliability, and moderate cost. It can improve the problem of reactive power distribution in the power system and solve the shortcomings of the reactive power compensation generator to a certain extent.

Description

Technical Field

[0001] The invention relates to the technical field of reactive power compensation for power grid lines, and more specifically to a static reactive power generator device with photovoltaic power generation. Background Art

[0002] The low voltage problem of distribution network has emerged in recent years with the development of national economy, and it is more common in economically underdeveloped areas. For the low voltage problem of distribution network, reactive power compensation can be selected, including traditional reactive power compensation (capacitors and reactors), dynamic reactive power compensation (SVC and SVG) and DG (distributed power source) with reactive power regulation capability.

[0003] The static VAR generator (SVG) is currently the most advanced reactive power compensation device in China. It relies on the power module to directly adjust reactive power in the power system. For its power module, it is generally powered directly by the power grid system, and outputs direct current to the reactive power generation device through the rectifier, and then outputs reactive current through the inverter circuit. The rectifier is relatively complex, and the power supply voltage will fluctuate with the fluctuation of the power grid, and the stability is insufficient. SVG can use the control operation module to automatically control the reactive current output. Generally, there is no additional communication machine to realize remote manual control. Moreover, under the green economic energy system advocated by my country, the utilization of clean energy is not strong. Summary of the invention

[0004] In order to overcome at least one defect of the above-mentioned prior art, the present invention provides a static reactive power generator device with photovoltaic power generation, which has simple structure, convenient installation, wireless control, remote debugging, green environmental protection, good reliability, and moderate cost. It can improve the problem of reactive power distribution in the power system and solve the shortcomings of the reactive power compensation generator to a certain extent.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is: a static VAR generator device with photovoltaic power generation, including a detection module, a control module, an IGBT-IPM module, a communication module, an energy storage system and a backup power supply, a solar panel and a voltage regulating transformer, the detection module, the IGBT-IPM module and the communication module are electrically connected to the control module respectively, the regulating transformer and the energy storage system are electrically connected to the IGBT-IPM module respectively, the backup power supply and the solar panel are electrically connected to the energy storage system respectively, and the backup power supply is electrically connected to the detection module.

[0006] Furthermore, the detection module leads to two groups of 3 incoming lines for measuring current and voltage, and connects to the three-phase circuit. The current A / D conversion and voltage A / D conversion collection technology is adopted, and the incoming line is measured by assembling PT and CT. The detection module inputs the three-phase voltage and three-phase current data of the system load point to the control module, performs the function of measuring and transmitting data, and has a charging function at the same time. There are 2 groups of incoming lines connected to the power grid as an AC power source, which is connected to a 380V AC power input through the line to charge the backup power battery, reserve the backup power supply, and prevent the occurrence of reactive compensation failure caused by insufficient light energy storage.

[0007] Furthermore, the communication module is provided with a communication signal input terminal and a communication signal output terminal, and contains a multi-mode communication chip, which supports Ethernet, WIFI, 4G and other modes to communicate with the remote master station, and also supports RS485, RS232, USB and CAN and other modes to connect with other local devices, so that the module can realize the functions of remote observation, maintenance and control.

[0008] Furthermore, the IGBT-IPM module is provided with a driving circuit, a protection circuit, an alarm output circuit and a braking circuit. The IGBT-IPM module is powered by the energy storage system, receives the input driving signal of the control module, converts the DC into AC through the internal inverter circuit, connects to the voltage regulating transformer, outputs reactive current, and regulates reactive power.

[0009] Furthermore, the energy storage system is a first DC battery. Direct DC is directly input, and no external rectifier module is required to convert AC into DC. The main power source of the energy storage system is the solar panel, plus a backup power supply to ensure the reliability of the device. The output end of the energy storage system is connected to a DC capacitor to maintain the voltage stability across the DC capacitor, and also provide a stable DC voltage for the IPM inverter circuit. The solar panel is the main source of power for the device. According to the requirements of the reactive power capacity that needs to be adjusted, it is generally matched at a loss rate of 3~5%, and a solar panel suitable for the power generation is selected.

[0010] Furthermore, the backup power supply is composed of a second DC battery, a switch and a rectifier device which are electrically connected in sequence. Through the incoming line of the detection module, it is indirectly connected to the power grid system for power storage, thereby solving the problem of insufficient power supply for the reactive compensation device caused by the instability of solar energy storage. The stored electric energy can be replenished at any time during the operation of the power grid to ensure the reliability of the reactive compensation device. At the same time, the backup power supply module can be automatically switched on and off through the switch device.

[0011] Compared with the prior art, the beneficial effects are:

[0012] In addition to using the IGBT-IPM module to intelligently realize the reactive power compensation function of the SVG device, the present invention also adds a communication module to facilitate remote maintenance and debugging. At the same time, clean energy solar energy is used as the power source of the SVG device, reducing the rectifier device required for the system AC power supply. It not only achieves clean energy, but also simplifies the device, is easy to install, and increases the backup power supply to maintain the reliability of the reactive power generator. It has a simple structure, is easy to install, has wireless control, remote debugging, is green and environmentally friendly, has good reliability, and can improve the problem of reactive power distribution in the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0014] Figure 2 It is a functional relationship connection diagram;

[0015] Figure 3 Run the flow chart for the control module;

[0016] Figure 4 Run the flow chart for the energy storage system. DETAILED DESCRIPTION

[0017] The drawings are only for illustrative purposes and cannot be construed as limiting the present invention. To better illustrate the present embodiment, some parts of the drawings may be omitted, enlarged, or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the drawings. The positional relationships described in the drawings are only for illustrative purposes and cannot be construed as limiting the present invention.

[0018] like Figure 1 As shown, a static VAR generator device with photovoltaic power generation includes a detection module, a control module, an IGBT-IPM module, a communication module, an energy storage system and a backup power supply, a solar panel and a voltage regulating transformer. The detection module, the IGBT-IPM module and the communication module are electrically connected to the control module respectively, the regulating transformer and the energy storage system are electrically connected to the IGBT-IPM module respectively, the backup power supply and the solar panel are electrically connected to the energy storage system respectively, and the backup power supply is electrically connected to the detection module.

[0019] The detection module leads to two groups of 3 incoming lines for measuring current and voltage to connect to the three-phase circuit. Using current A / D conversion and voltage A / D conversion collection technology, the incoming line is measured by assembling PT and CT. The detection module inputs the three-phase voltage and three-phase current data of the system load point to the control module to perform the functions of measuring and transmitting data. It also has a charging function. There are 2 groups of incoming lines connected to the grid as an AC power source. Through the line connection, it is a 380V AC power input to charge the backup power battery, reserve the backup power supply, and prevent the occurrence of reactive compensation failure caused by insufficient light energy storage.

[0020] The communication module is equipped with a communication signal input terminal and a communication signal output terminal, and contains a multi-mode communication chip. It supports Ethernet, WIFI, 4G and other modes to communicate with the remote master station, and also supports RS485, RS232, USB and CAN to connect with other local devices, so that the module can realize the functions of remote observation, maintenance and control.

[0021] The IGBT-IPM module is equipped with a drive circuit, a protection circuit, an alarm output circuit and a brake circuit. The IGBT-IPM module is powered by the energy storage system, receives the input drive signal from the control module, converts DC into AC through the internal inverter circuit, connects to the voltage regulating transformer, outputs reactive current, and regulates reactive power.

[0022] The energy storage system is the first DC battery. Direct DC is input, and no external rectifier module is required to convert AC into DC. The main power source of the energy storage system is the solar panel, plus a backup power supply to ensure the reliability of the device. The output end of the energy storage system is connected to a DC capacitor to maintain the voltage stability across the DC capacitor, and also provide a stable DC voltage for the IPM inverter circuit. The solar panel is the main source of power for the device. According to the requirements of the reactive power capacity that needs to be adjusted, it is generally matched at a loss rate of 3~5%, and the solar panel suitable for the power generation is selected.

[0023] The backup power supply is composed of a second DC battery, a switch and a rectifier device electrically connected in sequence. Through the incoming line of the detection module, it is indirectly connected to the power grid system for power storage, thereby solving the problem of insufficient power supply for the reactive compensation device caused by the instability of solar energy storage. The stored electric energy can be replenished at any time during the operation of the power grid to ensure the reliability of the reactive compensation device. At the same time, the backup power supply module can be automatically switched on and off through the switch device.

[0024] like Figure 2The functional relationship connection diagram of this system is shown. The detection module is indirectly connected to the power grid to store electricity for the backup power supply. The backup power supply and solar panels are connected to the energy storage system to provide a stable power supply for the energy storage system. The DC power supply is directly provided to the IGBT-IPM module through the energy storage system. The control module inputs the original load data through the detection module, and the control module analyzes the load information and outputs the drive signal to the IGBT-IPM module, outputs the load analysis data to the communication module, and transmits the data information to the remote master station or local equipment through the communication module for remote observation. The control module is controlled by the remote control signal fed back by the communication module. The IGBT-IPM module outputs reactive current and adjusts reactive power.

[0025] like Figure 3 As shown in the control module operation flow chart, referring to the reactive compensation capacity calculation coefficient table, the system automatically presets the output Qset. The basic principle is to use an iterative method to continuously correct the gap between the compensated reactive power Q and the set reactive power Qset that should be emitted, and finally achieve ideal reactive power compensation within the error (Qset*2%) operating range.

[0026] By measuring the load reactive power Q1 and calculating its deviation from Qset, when the absolute value of the error is less than e (Qset*2%), it is considered that the device output reactive power meets the requirements. When the absolute value of the error is greater than e, the actual reactive power to be adjusted Q0 is calculated.

[0027] If Q0 is not within the device adjustment range, it is adjusted according to its upper / lower power limit. If Q0 is within the device adjustment range, the reactive power adjusted by the device is corrected, and the iteration continues. Return to the step of measuring the load reactive power and repeat the measurement operation.

[0028] like Figure 4 As shown in the energy storage system operation flow chart, the rated capacity of each power source is first determined. The energy storage rated power capacity E0 is matched according to the upper limit of the reactive power regulation capacity Q*15h (hours) of the IPM module. The backup power supply capacity is matched according to 30% of the energy storage system rated power E0. The solar panels are generally matched according to a loss rate of 3~5%.

[0029] This process system is based on real-time monitoring and controls the switching of backup power supplies by measuring the electric energy E stored in the energy storage system, thereby enhancing the reliability of the photovoltaic system.

[0030] When the energy storage system's electric energy E is greater than its rated energy capacity E0*50%, there is no need to connect to the backup power supply, and the backup power supply does not need to be connected to the grid; when the energy storage system's electric energy E is less than its rated energy capacity E0*50%, the system will automatically open the connection between the backup power supply and the grid, start charging the backup power supply, and reserve the backup power supply energy.

[0031] When the energy storage system power E is less than the rated power capacity E0*20%, the system will automatically turn on the backup power supply to charge the energy storage system until the energy storage system power is greater than 20%, ensuring that the device can continue to operate at least when the photovoltaic power supply is insufficient. The reliability of the device is ensured by continuous cycle detection and switching control when power is insufficient.

[0032] In summary, the detection module in the static reactive generator device with photovoltaic power generation of the present invention is responsible for collecting the three-phase voltage and current information of the load point of the power system, and the control operation module is responsible for analyzing the current current information (PF, S, Q), and then outputting the compensated driving signal to the IGBT-IPM module. The solar panel performs photoelectric conversion and directly stores it in the form of DC in the energy storage system. The energy storage system serves as the power supply of the IPM module. In addition, it is also equipped with a corresponding DC backup power supply. The IGBT-IPM module is composed of an IGBT power electronic inverter circuit. After receiving the driving signal, it will output a compensation current, which will pass through a voltage regulating transformer and finally change the reactive power of the power system load.

[0033] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A static VAR generator device with photovoltaic power generation, characterized in that: It includes a detection module, a control module, an IGBT-IPM module, a communication module, an energy storage system and a backup power supply, a solar panel and a voltage regulating transformer. The detection module, the IGBT-IPM module and the communication module are electrically connected to the control module respectively, the voltage regulating transformer and the energy storage system are electrically connected to the IGBT-IPM module respectively, the backup power supply and the solar panel are electrically connected to the energy storage system respectively, and the backup power supply is electrically connected to the detection module; The detection module is indirectly connected to the power grid to store electricity for the backup power supply. The backup power supply and the solar panel are connected to the energy storage system to provide a stable power supply for the energy storage system, and a DC power supply is directly provided to the IGBT-IPM module through the energy storage system; the original load data is input to the control module through the detection module, the control module analyzes the load information and outputs a drive signal to the IGBT-IPM module, and outputs load analysis data to the communication module, and the data information is transmitted to a remote master station or a local device through the communication module for remote observation, and the remote control signal is fed back by the communication module to control the control module, and the IGBT-IPM module outputs reactive current and adjusts reactive power; Using an iterative approach, the gap between the compensated reactive power Q and the set reactive power Qset that should be emitted is continuously corrected, and finally the ideal reactive power compensation is achieved within the error Qset*2% operating range. Based on real-time monitoring, the backup power supply is controlled by measuring the stored energy E of the energy storage system: when the energy storage system energy E is greater than its rated energy capacity E0*50%, there is no need to connect to the backup power supply, and the backup power supply does not need to be connected to the grid. When the energy storage system energy E is less than its rated energy capacity E0*50%, the system will automatically open the connection between the backup power supply and the grid, start charging the backup power supply, and reserve the backup power supply energy. When the energy storage system energy E is less than the rated energy capacity E0*20%, the system will automatically open the backup power supply to charge the energy storage system until the energy storage system energy is greater than E0*20%, ensuring that the device can continue to operate when the photovoltaic power supply is insufficient.

2. A static VAR generator device with photovoltaic power generation according to claim 1, characterized in that: The detection module leads out two groups of three incoming lines each for measuring current and voltage and is connected to a three-phase circuit.

3. A static VAR generator device with photovoltaic power generation according to claim 1, characterized in that: The communication module is provided with a communication signal input terminal and a communication signal output terminal, and contains a multi-mode communication chip.

4. A static VAR generator device with photovoltaic power generation according to claim 1, characterized in that: The IGBT-IPM module is provided with a driving circuit, a protection circuit, an alarm output circuit and a braking circuit.

5. A static VAR generator device with photovoltaic power generation according to claim 1, characterized in that: The energy storage system is a first direct current battery.

6. A static VAR generator device with photovoltaic power generation according to claim 1, characterized in that: The backup power supply is composed of a second DC battery, a switch and a rectifier which are electrically connected in sequence.

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