Method and device for controlling operation mode of photovoltaic inverter and electronic equipment

Abstract

The invention discloses a photovoltaic inverter operation mode control method and device and electronic equipment. The method comprises the following steps: acquiring a power grid parameter at a current moment and a current operation mode of a photovoltaic inverter; determining a next operation mode of the photovoltaic inverter according to the power grid parameters and the current operation mode; if the current operation mode is a network following operation mode and the next operation mode is a network construction operation mode, switching to the network construction operation mode through control of the virtual oscillator, and controlling the photovoltaic inverter to operate according to the network construction operation mode; and if the current operation mode is a network construction operation mode and the next operation mode is a network following operation mode, switching to the network following operation mode through control of the virtual oscillator, and controlling the photovoltaic inverter to operate according to the network following operation mode. According to the method, the dynamic change of the power grid can be quickly responded, and a smooth and stable switching process is realized, so that the continuous operation capability of the system is enhanced, and the overall reliability is remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic inverter technology, specifically relating to a control method, device, and electronic equipment for the operation mode of a photovoltaic inverter. Background Technology

[0002] Currently, photovoltaic inverters employ phase-locked loop (PLL) technology in the switching control between grid-connected and grid-connected operation modes. However, this method has significant drawbacks: First, the phase needs to be relocked during the switching process, which can easily lead to brief phase loss and phase jumps, causing sudden changes in voltage and current, affecting the smoothness and stability of the system. Second, the PLL response speed is slow, especially in weak grids or situations with poor signal quality, where the locking process takes a long time and it is difficult to quickly adapt to changes in the grid, thus limiting the dynamic performance of the system. Third, the system needs to be shut down during the switching process to wait for the phase-locking to complete, making it difficult to achieve truly seamless and smooth switching, affecting the continuous operation and overall reliability of the system. Summary of the Invention

[0003] The technical problem to be solved by this invention is to address the aforementioned shortcomings of existing technologies by proposing a control method, device, and electronic equipment for the operating mode of a photovoltaic inverter. This method can quickly respond to dynamic changes in the power grid, achieve a smooth and stable switching process, thereby enhancing the continuous operation capability of the system and significantly improving overall reliability.

[0004] In a first aspect, the present invention provides a method for controlling the operating mode of a photovoltaic inverter, the method comprising the following steps:

[0005] Obtain the current grid parameters; and obtain the current operating mode of the photovoltaic inverter;

[0006] Determine the next operating mode of the photovoltaic inverter based on grid parameters and the current operating mode;

[0007] If the current operating mode is grid-following mode and the next operating mode is grid-building mode, then the photovoltaic inverter is controlled to switch from grid-following mode to grid-building mode through the virtual oscillator, and the photovoltaic inverter is controlled to operate according to the grid-building mode.

[0008] If the current operating mode is grid-connected operating mode and the next operating mode is grid-following operating mode, then the photovoltaic inverter is controlled to switch from grid-connected operating mode to grid-following operating mode through the virtual oscillator, and the photovoltaic inverter is controlled to operate in grid-following operating mode.

[0009] Furthermore, based on grid parameters and the current operating mode, the next operating mode of the photovoltaic inverter is determined, specifically including:

[0010] If the grid parameters are within the preset parameter threshold range and the current operating mode is grid-following operation mode, then the next operating mode of the photovoltaic inverter is determined to be grid-following operation mode;

[0011] If the grid parameters are not within the preset parameter threshold range and the current operating mode is grid-following operation mode, then the next operating mode of the photovoltaic inverter is determined to be grid-connected operation mode;

[0012] If the grid parameters are within the preset parameter threshold range and the current operating mode is the grid-connected operating mode, then the next operating mode of the photovoltaic inverter will still be the grid-connected operating mode.

[0013] If the grid parameters are not within the preset parameter threshold range and the current operating mode is the grid-connected operating mode, then the next operating mode of the photovoltaic inverter will still be the grid-connected operating mode.

[0014] Furthermore, the photovoltaic inverter is controlled to switch from grid-connected operation mode to grid-connected operation mode via a virtual oscillator, specifically including:

[0015] Obtain the initial conditions for the network operation mode;

[0016] Based on the initial conditions of the network operation mode, the AC voltage loop is enabled by a virtual oscillator;

[0017] The initial control state of the network operation mode is obtained based on the AC voltage loop.

[0018] Based on the initial control state of the network construction operation mode, the virtual oscillator is used to switch from the network following operation mode to the network construction operation mode.

[0019] Furthermore, the initial conditions for obtaining the network operation mode specifically include:

[0020] The DQ axis components of the current grid-connected current are assigned to the integral term of the PI controller in the AC voltage loop to obtain the initial conditions for the grid operation mode.

[0021] Based on the AC voltage loop, the initial control state of the grid operation mode is obtained, specifically including:

[0022] Based on the voltage reference signal provided by the AC voltage loop, the virtual oscillator loop is subjected to anti-saturation processing to obtain the anti-saturation processing result;

[0023] Based on the anti-saturation processing results, the virtual oscillator control loop is enabled and the power decoupling module is disabled to obtain the initial control state of the network operation mode.

[0024] Furthermore, the switching from network-following operation mode to network-building operation mode is performed through a virtual oscillator, specifically including:

[0025] Switch the phase angle from the phase angle output of the phase-locked loop to the phase angle output of the virtual oscillator; and,

[0026] Switch the AC current from the current output of the power decoupling module to the current output of the AC voltage loop;

[0027] Among them, the phase angle output of the phase-locked loop and the current output of the power decoupling module are both outputs in grid-following operation mode; the phase angle output of the virtual oscillator and the current output of the AC voltage loop are both outputs in grid-connected operation mode.

[0028] The current output of the power decoupling module includes I d_ref_gfl and I q_ref_gfl The current output of the AC voltage loop includes I. d_ref_gfm I q_ref_gfm ;

[0029] I d_ref_gfl This indicates the reference value of the DC component current in grid-connected operation mode;

[0030] I q_ref_gfl This indicates the reference value of the cross component current in grid-connected operation mode;

[0031] I d_ref_gfm This indicates the reference value of the DC component current under the grid-connected operation mode;

[0032] I q_ref_gfm This indicates the reference value of the cross component current in the network operation mode.

[0033] Furthermore, the photovoltaic inverter is controlled to switch from grid-connected operation mode to grid-following operation mode via a virtual oscillator, specifically including:

[0034] Release the control logic that controls the network operation mode to obtain the initial conditions for the network operation mode;

[0035] Among them, the control logic release in the network operation mode includes: disabling the AC voltage loop module and controlling the AC voltage loop to stop calculation; and disabling the virtual oscillator control loop module and controlling the virtual oscillator loop to stop calculation;

[0036] Based on the initial conditions of the grid-following operation mode, the power decoupling module is enabled by a virtual oscillator and the power decoupling module is controlled to start calculation, thereby obtaining the initial control state of the grid-following operation mode.

[0037] Based on the initial control state of the grid-following operation mode, the virtual oscillator is used to switch the grid-building operation mode to the grid-following operation mode.

[0038] Furthermore, the switching from network-building operation mode to network-following operation mode is performed through a virtual oscillator, specifically including:

[0039] Switch the phase angle from the phase angle output of the virtual oscillator to the phase angle output of the phase-locked loop; and,

[0040] Switch the AC current from the current output of the AC voltage loop to the current output of the power decoupling module;

[0041] Among them, the phase angle output of the phase-locked loop and the current output of the power decoupling module are both outputs in grid-following operation mode; the phase angle output of the virtual oscillator and the current output of the AC voltage loop are both outputs in grid-connected operation mode.

[0042] The current output of the power decoupling module includes I d_ref_gfl and I q_ref_gfl The current output of the AC voltage loop includes I. d_ref_gfm I q_ref_gfm ;

[0043] I d_ref_gfl This indicates the reference value of the DC component current in grid-connected operation mode;

[0044] I q_ref_gfl This indicates the reference value of the cross component current in grid-connected operation mode;

[0045] I d_ref_gfm This indicates the reference value of the DC component current under the grid-connected operation mode;

[0046] I q_ref_gfm This indicates the reference value of the cross component current in the network operation mode.

[0047] In a second aspect, the present invention provides a control device for the operating mode of a photovoltaic inverter, the device comprising:

[0048] The acquisition unit is used to acquire the current grid parameters and the current operating mode of the photovoltaic inverter.

[0049] The determination unit, connected to the acquisition unit, is used to determine the next operating mode of the photovoltaic inverter based on grid parameters and the current operating mode.

[0050] The detection unit, connected to the acquisition unit and the determination unit respectively, is used to detect the current operating mode and the next operating mode;

[0051] The first control unit is connected to the detection unit and is used to control the photovoltaic inverter to switch from the grid-following operation mode to the grid-building operation mode through a virtual oscillator when the detection unit detects that the current operation mode is the grid-following operation mode and the next operation mode is the grid-building operation mode, and to control the photovoltaic inverter to operate according to the grid-building operation mode.

[0052] The second control unit is connected to the detection unit and is used to control the photovoltaic inverter to switch from the grid-connected operation mode to the grid-connected operation mode through a virtual oscillator when the detection unit detects that the current operation mode is the grid-connected operation mode and the next operation mode is the grid-following operation mode, and to control the photovoltaic inverter to operate in the grid-connected operation mode.

[0053] Furthermore, the defined unit includes:

[0054] The first determining unit, connected to the acquiring unit, is used to determine the next operating mode of the photovoltaic inverter as the grid-following operating mode when the grid parameters are within the preset parameter threshold range and the current operating mode is the grid-following operating mode.

[0055] The second determining unit, connected to the acquiring unit, is used to determine the next operating mode of the photovoltaic inverter as the grid-connected operating mode when the grid parameters are not within the preset parameter threshold range and the current operating mode is the grid-connected operating mode.

[0056] The third determining unit, connected to the acquiring unit, is used to determine that the next operating mode of the photovoltaic inverter is still the grid-connected operating mode when the grid parameters are within the preset parameter threshold range and the current operating mode is the grid-connected operating mode.

[0057] The fourth determining unit, connected to the acquiring unit, is used to determine the next operating mode of the photovoltaic inverter as the grid-connected operating mode when the grid parameters are not within the preset parameter threshold range and the current operating mode is the grid-connected operating mode.

[0058] Thirdly, the present invention provides an electronic device including a memory and a processor, wherein the memory stores a computer program, and when the processor runs the computer program stored in the memory, the processor executes the control method for the photovoltaic inverter operating mode according to the first aspect.

[0059] This invention introduces a control method based on a virtual oscillator, which enables rapid response to dynamic changes in the power grid and achieves a smooth and stable switching process, thereby improving the system's adaptability and stability. Specific beneficial effects are as follows:

[0060] 1. The present invention employs virtual oscillator technology, which enables rapid adaptation to changes in grid parameters, improves system response speed and continuity, and ensures more sensitive and timely switching between grid-connected and grid-connected operation modes.

[0061] 2. This invention enables autonomous adjustment, reduces human intervention, improves the system's automation level, and enhances the system's intelligent management capabilities.

[0062] 3. This invention employs a virtual oscillator, which enables a smooth transition when the photovoltaic inverter switches operating modes, reducing voltage fluctuations and harmonic pollution that may occur during the switching process, and enhancing the stability of the power grid. Attached Figure Description

[0063] Figure 1 This is a schematic diagram of the control method for the operation mode of a photovoltaic inverter in an embodiment of the present invention;

[0064] Figure 2 This is a control block diagram of the two-level network operation mode in an embodiment of the present invention;

[0065] Figure 3 This is a block diagram of the single-level network operation mode control in an embodiment of the present invention;

[0066] Figure 4 This is a control block diagram of the two-level network construction operation mode in an embodiment of the present invention;

[0067] Figure 5 This is a control block diagram of the single-level network operation mode in an embodiment of the present invention;

[0068] Figure 6 This is a schematic diagram of the control device for the operation mode of a photovoltaic inverter in an embodiment of the present invention;

[0069] Figure 7 This is an architectural diagram of an electronic device according to an embodiment of the present invention.

[0070] Reference numerals: 10, acquisition unit; 20, determination unit; 30, control unit; 100, processor; 200, memory. Detailed Implementation

[0071] To enable those skilled in the art to better understand the technical solution of the present invention, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0072] It is understood that the specific embodiments and accompanying drawings described herein are merely for explaining the invention and are not intended to limit the invention.

[0073] It is understood that, without conflict, the various embodiments and features in the embodiments of the present invention can be combined with each other.

[0074] It is understood that, for ease of description, only the parts related to the present invention are shown in the accompanying drawings, while the parts unrelated to the present invention are not shown in the drawings.

[0075] It is understood that each unit or module involved in the embodiments of the present invention may correspond to only one entity structure, or may be composed of multiple entity structures, or multiple units or modules may be integrated into one entity structure.

[0076] It is understood that, without conflict, the functions and steps marked in the flowcharts and block diagrams of this invention may occur in a different order than that marked in the accompanying drawings.

[0077] It is understood that the flowcharts and block diagrams of this invention illustrate the possible architecture, functions, and operations of systems, apparatuses, devices, and methods according to various embodiments of this invention. Each block in the flowchart or block diagram may represent a unit, module, program segment, or code, containing executable instructions for implementing the specified function. Furthermore, each block or combination of blocks in the block diagram and flowchart can be implemented using a hardware-based system to achieve the specified function, or using a combination of hardware and computer instructions.

[0078] It is understood that the units and modules involved in the embodiments of the present invention can be implemented by software or by hardware. For example, the units and modules can be located in a processor.

[0079] Currently, photovoltaic (PV) inverters commonly employ phase-locked loop (PLL) technology to synchronize with the grid, regardless of whether they are operating in grid-connected or grid-connected mode. However, this method has some limitations, the details of which have been described in detail above and will not be repeated here. Based on this, this invention proposes an innovative PV inverter operating mode control method. This method enables faster grid response and smooth transitions during mode switching, ensuring system stability and reliability. This control strategy significantly improves the continuous operation capability of the PV inverter system and enhances the overall reliability of the entire system.

[0080] The hardware components and control stages of a photovoltaic inverter operating system are detailed below:

[0081] 1. The photovoltaic inverter operating system mainly includes the following hardware modules, such as... Figure 2 As shown:

[0082] 1.1 BOOST voltage loop module:

[0083] A photovoltaic inverter can be a two-stage photovoltaic inverter or a single-stage photovoltaic inverter.

[0084] like Figure 2 As shown, for a two-stage grid-connected photovoltaic inverter, the front-end BOOST control loop mainly realizes the maximum power point tracking (MPPT) function of the photovoltaic panels. Its input signal is the real-time sampling of the BOOST module's input voltage, i.e., the PV voltage V of the photovoltaic module. pv The output signal V of the MPPT module pv_ref The output signal is the given signal I of the BOOST current loop. pv_refThis loop mainly controls the photovoltaic panel voltage to track the output voltage command of the MPPT module in real time, thereby achieving the maximum power point tracking function.

[0085] For single-stage photovoltaic inverters, there is no such BOOST voltage loop module, such as... Figure 3 As shown.

[0086] 1.2 BOOST Current Loop Module:

[0087] The BOOST current loop primarily controls the BOOST side current, and its input is the output signal I of the BOOST voltage loop. pv_ref The input current of the BOOST module is the PV current I of the photovoltaic panel. pv The output is the PWM drive signal on the BOOST side. This module enables the BOOST current to track the command signal output by the BOOST voltage loop in real time, and finally realizes MPPT control.

[0088] For single-stage photovoltaic inverters, there is no such BOOST current loop module, such as... Figure 3 As shown.

[0089] 1.3 DC bus voltage loop module:

[0090] For a two-stage grid-connected photovoltaic inverter, the DC bus voltage loop is used to control the DC bus voltage and balance the power on the BOOST side and the inverter side. Its input is V. bus_ref and the real-time acquired DC-side bus voltage V bus The output is the active power command signal P. ref , which serves as the input signal for the power decoupling module.

[0091] Where V bus_ref This is the given signal for the bus voltage, typically the peak value of the AC voltage.

[0092] For a single-stage photovoltaic inverter, the photovoltaic modules are directly connected to the DC bus. The DC bus voltage loop is used to stabilize the DC bus voltage and also realize the MPPT function.

[0093] 1.4 Power Decoupling Module:

[0094] This module combines the current real-time grid voltage and power commands to calculate real-time active and reactive current commands. The input signal is the output signal P from the DC bus voltage loop module. ref Reactive power dispatching command Q ref The grid voltage DQ axis components Vd and Vq are output as the input signal I of the AC current loop module. d_ref_gfl I q_ref_gfl I d_ref_gfl I q_ref_gfl The calculation formula is as follows:

[0095]

[0096] I d_ref_gfl Indicates the reference value of the DC component (D-axis) current;

[0097] I q_ref_gfl This indicates the reference value for the cross component (Q-axis) current.

[0098] 1.5 AC Current Loop Module:

[0099] The AC current loop controls the inverter-side current; its input signal is the output signal I from the power decoupling module. d_ref_gf I q_ref_gf The DQ axis voltage I after the three-phase inverter current passes through the PARK converter d I q The output is the inverter-side PWM drive signal.

[0100] 1.6 Phase-Locked Loop Module:

[0101] The phase-locked loop module realizes the function of tracking the phase of the grid voltage. The input is three-phase voltage and the output is phase angle.

[0102] 1.7 3S / 2R Module:

[0103] The 3S / 2R module is a key component used in power electronic systems for coordinate transformation and phase detection of voltage and current signals. Its full name is usually "Three-phase stationary coordinate system (abc) to rotating coordinate system (DQ) transformation module." Its main function is to transform physical quantities such as three-phase voltage and current in a three-phase AC system from a continuous three-phase stationary coordinate system (abc coordinates) to a rotating orthogonal coordinate system (DQ coordinates). This transforms the voltage and current quantities in the three-phase stationary coordinate system (abc) into the direct axis (D-axis) and quadrature axis (Q-axis) coordinate systems that rotate with the rotor, thereby simplifying the control algorithm and improving the efficiency and accuracy of regulation.

[0104] 2. The photovoltaic inverter operating system mainly includes the following control stages:

[0105] 2.1 BOOST boosting stage:

[0106] Figure 4 The diagram shown is a two-stage grid operation mode control block diagram. The BOOST boost stage includes a BOOST voltage loop and a BOOST current loop. After extracting the maximum power point of the photovoltaic cells through the MPPT (Maximum Power Point Tracking) controller, the PWM control signal on the BOOST side is generated through voltage PI regulation and current PI regulation respectively, thereby achieving stable voltage boost from the photovoltaic side to the bus.

[0107] Figure 5The control block diagram of the single-stage grid operation mode is shown. The difference between the two-stage grid operation mode control and the two-stage grid operation mode control is that there is no need for a BOOST boost stage. The photovoltaic output is directly connected to the grid control part to achieve integrated control.

[0108] 2.2 DC bus voltage loop:

[0109] Used to control the stability of the bus voltage Vbus, ensuring that the photovoltaic inverter operates under ideal DC voltage.

[0110] The reference voltage is output from the PI regulator and then enters the power decoupling module.

[0111] 2.3 Power Decoupling and Virtual Synchronization Control:

[0112] By using the preset power reference value (P) ref With Q ref Based on the bus voltage and current information, the required current reference value i for network construction is calculated. d with i q .

[0113] The decoupling algorithm takes into account parameters such as voltage amplitude and phase, making network control more precise and response more stable.

[0114] 2.4 AC Current Loop:

[0115] Use a dual PI controller to adjust i separately. d and i q Output voltage control commands. Improve the system's current tracking capability and dynamic response performance.

[0116] 2.5SPWM (Sinusoidal Pulse Width Modulation) modulation and control output:

[0117] The regulated voltage command signal is converted into a three-phase PWM waveform by the SPWM module, which drives the three arms (PWM_A, PWM_B, PWM_C) of the photovoltaic inverter to complete the grid output.

[0118] 2.6 Coordinate Transformation and PLL Phase-Locked Loop:

[0119] It includes a three-phase stationary coordinate system to rotating coordinate system (3S / 2R) transformation module and a phase-locked loop (PLL) for power grid synchronization and decoupling control.

[0120] Example 1:

[0121] This embodiment provides a control method for the operating mode of a photovoltaic inverter. This method can be applied to distributed photovoltaic power generation systems and smart microgrids, and is particularly suitable for scenarios with complex and changing multi-grid environments, such as distributed generation, urban microgrids, multi-source grid connection, and smart grid systems requiring efficient and seamless switching. This method can cope with frequent fluctuations in grid parameters and changes in signal quality, adjusting the operating state of the photovoltaic inverter in real time to ensure stable operation under different grid conditions. Simultaneously, it enables efficient grid connection and reliable power supply from the photovoltaic power generation system, meeting the needs of intelligent management and grid integration in modern green energy.

[0122] like Figure 1 As shown, the control method for the photovoltaic inverter operating mode in this embodiment specifically includes the following steps:

[0123] Step S1: Obtain the current grid parameters; and obtain the current operating mode of the photovoltaic inverter.

[0124] The current operating mode is either grid-connected or grid-connected. Grid-connected operation mode means that the photovoltaic inverter operates as a slave device, outputting frequency and voltage synchronously with the grid; grid-connected operation mode means that the photovoltaic inverter operates as a master device, using a virtual oscillator to generate independent voltage and frequency signals.

[0125] Obtaining the current grid parameters and the current operating mode of the photovoltaic inverter is a fundamental step in achieving intelligent switching. Grid parameters include voltage amplitude (V), frequency (f) / angular frequency (ω), phase information, and grid current. These parameters are acquired in real time using voltage probes, current sensors, and high-speed sampling equipment.

[0126] Step S2: Determine the next operating mode of the photovoltaic inverter based on the grid parameters and the current operating mode; the next operating mode is either grid-connected operation mode or grid-connected operation mode.

[0127] As a specific implementation method, the next operating mode of the photovoltaic inverter is determined based on grid parameters and the current operating mode, specifically including one of the following four situations:

[0128] Scenario 1: If the grid parameters are within the preset parameter threshold range and the current operating mode is grid-following operation mode, then the next operating mode of the photovoltaic inverter is determined to be grid-following operation mode.

[0129] Scenario 2: If the grid parameters are not within the preset parameter threshold range and the current operating mode is grid-connected operating mode, then the next operating mode of the photovoltaic inverter is determined to be grid-connected operating mode.

[0130] Scenario 3: If the grid parameters are within the preset parameter threshold range and the current operating mode is grid-connected operating mode, then the next operating mode of the photovoltaic inverter will still be grid-connected operating mode.

[0131] Scenario 4: If the grid parameters are not within the preset parameter threshold range and the current operating mode is the grid-connected operating mode, then the next operating mode of the photovoltaic inverter will still be the grid-connected operating mode.

[0132] In the intelligent control strategy of photovoltaic inverters, rationally judging and switching operating modes is a key link in ensuring the stable and safe operation of the system. The specific implementation process is based on real-time monitoring of grid parameters and the current operating mode (or operating state) of the photovoltaic inverter, dynamically deciding on the next operating mode to ensure that the system can respond appropriately to changes in the grid environment. The following details the principles and logic for determining the operating mode.

[0133] 1) Basic basis:

[0134] Power grid parameters include key indicators such as voltage amplitude, frequency, and phase difference. To ensure system safety, a set of predefined parameter thresholds are usually set (e.g., voltage ±10%, frequency ±0.5Hz). When the parameters are detected to be within these safe ranges, the power grid environment is considered stable.

[0135] Current operating mode: The photovoltaic inverter may be in "grid-following" mode (synchronized with the grid) or "grid-building" mode (autonomous control using a virtual oscillator, with power supply operating autonomously).

[0136] 2) Specific judgment rules:

[0137] The following are the rules used after each test to determine the next operating mode (or operating state) of the photovoltaic inverter.

[0138] Scenario 1: The power grid is stable and currently operating in grid-connected mode:

[0139] Conditions: All grid parameters are within the preset safe range (indicating normal voltage, frequency close to 50Hz or 60Hz, and no significant phase angle deviation); at the same time, the photovoltaic inverter is currently in a "grid-connected" state.

[0140] Judgment: Continue to maintain the "grid-synchronized" operation mode (or operating status). This situation means that the grid environment is normal, the photovoltaic inverter does not need to adjust the control strategy, and can continue to output synchronously.

[0141] Scenario 2: The power grid is unstable and the current operation mode is grid-connected:

[0142] Conditions: The grid parameters are detected to exceed the threshold (e.g., voltage drop, large voltage fluctuation, or abnormal frequency); while the photovoltaic inverter was originally in "grid-following" mode.

[0143] Judgment result: Switch to "grid" mode. / / At this time, the photovoltaic inverter should use a virtual oscillator to generate autonomous voltage and frequency signals to maintain power supply continuity and system stability.

[0144] Scenario 3: The power grid is stable and currently in grid-connected operation mode:

[0145] Conditions: The grid parameters are within the normal range, but the photovoltaic inverter is currently in the "grid-connected" state.

[0146] Judgment result: Maintain "grid-synchronous" mode. At this time, the system management side determines, based on the grid conditions, that the photovoltaic inverter can switch back to synchronous grid operation to achieve maximum energy efficiency and better power quality.

[0147] Scenario 4: The power grid is unstable and currently in grid-connected operation mode:

[0148] Condition: The grid parameters exceed the safe preset range, but the photovoltaic inverter is still in the "grid construction" state.

[0149] Judgment: Maintain "grid-based" mode. This is to avoid frequent switching during momentary grid anomalies, ensure the system's continuous autonomous control capability, and prevent unnecessary and drastic control switching that could cause system oscillations.

[0150] Step S3: If the current operating mode is grid-connected operation mode and the next operating mode is grid-connected operation mode, then the photovoltaic inverter is controlled to switch from grid-connected operation mode to grid-connected operation mode via a virtual oscillator, and the photovoltaic inverter is controlled to operate according to the grid-connected operation mode; if the current operating mode is grid-connected operation mode and the next operating mode is grid-connected operation mode, then the photovoltaic inverter is controlled to switch from grid-connected operation mode to grid-connected operation mode via a virtual oscillator, and the photovoltaic inverter is controlled to operate according to the grid-connected operation mode. That is, the photovoltaic inverter is controlled to operate according to the next operating mode.

[0151] As a specific implementation method, controlling the photovoltaic inverter to operate according to the next operating mode specifically includes:

[0152] If the current mode is grid-connected operation mode and the next operation mode is grid-connected operation mode, then control the photovoltaic inverter to switch from grid-connected operation mode to grid-connected operation mode; or,

[0153] If the current mode is grid-connected operation mode and the next operation mode is grid-following operation mode, then control the photovoltaic inverter to switch from grid-connected operation mode to grid-following operation mode.

[0154] As a specific implementation method, controlling the photovoltaic inverter to switch from grid-connected operation mode to grid-connected operation mode includes the following steps:

[0155] The DQ axis components of the current grid-connected current are assigned to the integral term of the PI controller in the AC voltage loop to obtain the initial conditions for the grid operation mode.

[0156] Enable the AC voltage loop based on the initial conditions of the network operation mode;

[0157] Based on the voltage reference signal provided by the AC voltage loop, the virtual oscillator loop is subjected to anti-saturation processing to obtain the anti-saturation processing result;

[0158] Based on the anti-saturation processing results, enable the virtual oscillator control loop and disable the power decoupling module to obtain the initial control state of the network operation mode;

[0159] Based on the initial control state of the network construction operation mode, the virtual oscillator is used to switch from the network following operation mode to the network construction operation mode.

[0160] In a two-stage photovoltaic inverter, switching from grid-connected operation mode to grid-connected operation mode requires coordinated control of the BOOST boost circuit and the photovoltaic inverter control loop: First, by sampling the DQ axis component i of the grid-connected current. d i q It is directly assigned to the integral term I of the AC voltage loop PI controller. d_int I q_int The current grid current state is inherited as the initial condition; subsequently, the AC voltage loop is enabled to output a stable voltage reference signal V based on the initial integral value. d_ref V q_ref At this time, the DC bus voltage V dc The BOOST circuit still maintains the reference value required for grid connection; then, to avoid output saturation of the virtual oscillator due to initial state differences, the voltage V provided by the AC voltage loop needs to be adjusted. d_ref V q_ref The virtual oscillator loop undergoes anti-saturation processing (e.g., limiting the integral term growth rate or dynamically adjusting the gain) to ensure a smooth transition of its output voltage command. After anti-saturation processing, the virtual oscillator control loop is enabled to generate the sinusoidal voltage reference required for off-grid operation, and the power decoupling module is disabled (because it relies on grid voltage phase information and fails in off-grid mode). At this point, the BOOST circuit needs to quickly respond to the power demand of the virtual oscillator, adjusting V... dc The grid connection reference value is adjusted to the grid construction reference value. Finally, after completing the above control state switching, the grid connection switch is disconnected, and the photovoltaic inverter is completely disconnected from the grid. It enters the grid construction operation mode dominated by the virtual oscillator and independently supported by the DC bus by the BOOST circuit, realizing a seamless transition from "grid following" to "voltage source active support".

[0161] In single-stage photovoltaic inverters, since the topology lacks an independent BOOST boost circuit, the core of mode switching lies in the dynamic adjustment of the photovoltaic inverter's own control strategy: First, it also samples the DQ-axis component i of the grid-connected current. d i q This value is assigned to the integral term I of the AC voltage loop PI controller. d_int I q_int This serves as the initial condition for the network operation mode; subsequently, the AC voltage loop is enabled, at which point the DC bus voltage V... dc The voltage is directly regulated by the photovoltaic modules via the MPPT algorithm (affected by light intensity), and its reference value needs to quickly match the voltage range required by the grid operation mode (such as relying on the maximum power point voltage of the photovoltaic modules); since the single-stage topology lacks a BOOST circuit to assist in regulating V... dc Dynamic balance needs to be achieved through the coordinated control of a virtual oscillator and MPPT. After the virtual oscillator generates the target voltage reference, the MPPT algorithm needs to adjust the operating point of the photovoltaic module in real time to ensure that V dc In grid-connected operation mode, the voltage stabilizes within a reasonable range. Next, anti-saturation processing of the virtual oscillator loop is performed (similar to the two-stage method) to prevent output voltage command distortion due to initial state differences. After anti-saturation, the virtual oscillator control loop is enabled to generate an off-grid voltage reference, and the power decoupling module (which relies on grid phase information) is disabled. Finally, ensuring that the photovoltaic module output power matches the load demand, the grid-connected switch is disconnected, and the photovoltaic inverter enters a state where the virtual oscillator is the core, relying on MPPT dynamic adjustment of the voltage. dc Although the grid-connected operation mode lacks the assistance of a BOOST circuit, stable off-grid voltage output can still be achieved through control algorithm optimization.

[0162] As a more specific implementation method, the switching from network-following operation mode to network-building operation mode is performed through a virtual oscillator, specifically including:

[0163] Switch the phase angle from the phase angle output of the phase-locked loop to the phase angle output of the virtual oscillator; and,

[0164] Switch the AC current from the current output of the power decoupling module to the current output of the AC voltage loop;

[0165] Among them, the phase angle output of the phase-locked loop and the current output of the power decoupling module are both outputs in grid-following operation mode; the phase angle output of the virtual oscillator and the current output of the AC voltage loop are both outputs in grid-connected operation mode.

[0166] The current output of the power decoupling module includes I d_ref_gfl and I q_ref_gfl The current output of the AC voltage loop includes I. d_ref_gfm I q_ref_gfm ;

[0167] I d_ref_gfl This indicates the reference value of the DC component current in grid-connected operation mode;

[0168] I q_ref_gfl This indicates the reference value of the cross component current in grid-connected operation mode;

[0169] I d_ref_gfm This indicates the reference value of the DC component current under the grid-connected operation mode;

[0170] I q_ref_gfm This indicates the reference value of the cross component current in the network operation mode.

[0171] As a specific implementation method, controlling the photovoltaic inverter to switch from grid-connected operation mode to grid-linked operation mode includes the following steps:

[0172] Release the control logic that controls the network operation mode to obtain the initial conditions for the network operation mode;

[0173] The control logic release in the network construction operation mode includes:

[0174] Disable the AC voltage loop module and stop the AC voltage loop calculation; and disable the virtual oscillator control loop module and stop the virtual oscillator loop calculation.

[0175] Based on the initial conditions of the grid-following operation mode, enable the power decoupling module and control the power decoupling module to start calculation to obtain the initial control state of the grid-following operation mode.

[0176] Based on the initial control state of the network-following operation mode, the switch from the network-building operation mode to the network-following operation mode is executed.

[0177] As a more specific implementation method, the switching from network construction operation mode to network following operation mode includes:

[0178] Switch the phase angle from the phase angle output of the virtual oscillator to the phase angle output of the phase-locked loop; and,

[0179] Switch the AC current from the current output of the AC voltage loop to the current output of the power decoupling module;

[0180] Among them, the phase angle output of the phase-locked loop and the current output of the power decoupling module are both outputs in grid-following operation mode; the phase angle output of the virtual oscillator and the current output of the AC voltage loop are both outputs in grid-connected operation mode.

[0181] The current output of the power decoupling module includes I d_ref_gfl and I q_ref_gfl The current output of the AC voltage loop includes I. d_ref_gfm Iq_ref_gfm ;

[0182] I d_ref_gfl This indicates the reference value of the DC component current in grid-connected operation mode;

[0183] I q_ref_gfl This indicates the reference value of the cross component current in grid-connected operation mode;

[0184] I d_ref_gfm This indicates the reference value of the DC component current under the grid-connected operation mode;

[0185] I q_ref_gfm This indicates the reference value of the cross component current in the network operation mode.

[0186] In a two-stage photovoltaic inverter, switching from grid-connected operation mode to grid-linked operation mode requires coordinated control of the BOOST boost circuit, the photovoltaic inverter control loop, and the grid-connected switch. First, the grid-connected operation mode control logic must be released, specifically including disabling the AC voltage loop module (stopping its access to V). d_ref V q_ref The calculation) and the virtual oscillator control loop module (stop generating off-grid sinusoidal voltage reference), at which time the DC bus voltage V dc The BOOST circuit maintains the reference value in the grid-connected operation mode. Subsequently, based on the initial conditions after the grid-connected operation mode is released (such as the last output voltage reference value of the virtual oscillator and the residual state of the power decoupling module), the power decoupling module is enabled and its calculations are started. The power decoupling module begins to generate active / reactive current reference I based on the grid voltage phase information. d_ref I q_ref At the same time, the BOOST circuit needs to respond quickly to power changes, converting V... dc Adjust from the grid-connected reference value to the grid-connected reference value (e.g., 600V, to match the grid voltage requirements); then, based on the current reference value output by the power decoupling module and the stable V after BOOST adjustment. dc The initial control state for grid-connected operation is established; finally, a switching operation is performed: the phase angle is switched from the output of the virtual oscillator in grid-connected operation mode to the grid synchronization phase θ of the phase-locked loop (PLL) in grid-connected operation mode. grid The voltage reference value previously controlled by the AC voltage loop is replaced with the current reference value of the AC current loop (determined by the power decoupling module based on the grid voltage V). grid and power command P ref Q ref (Dynamically generated), after the switch is completed, the grid-connected switch is closed, and the photovoltaic inverter switches from the off-grid mode dominated by the virtual oscillator to the grid-connected mode synchronized by the phase-locked loop. The BOOST circuit continuously adjusts V dc This is to ensure that the output of the photovoltaic inverter is strictly synchronized with the grid voltage.

[0187] In single-stage photovoltaic inverters, since there is no independent BOOST boost circuit, the core of mode switching lies in the dynamic adjustment of the photovoltaic inverter control strategy and the coordinated optimization of photovoltaic module output: First, the grid-connected operation mode control logic is released, including disabling the AC voltage loop module (stopping the generation of off-grid voltage reference) and the virtual oscillator control loop module (stopping the output of sinusoidal voltage commands). At this time, the DC bus voltage V dc The dynamic value maintained by the photovoltaic modules through the MPPT algorithm is determined (affected by light intensity); subsequently, based on the initial conditions after the grid operation mode is released (such as the voltage reference residual state at the last output of the virtual oscillator), the power decoupling module is enabled and its calculation is started. The power decoupling module generates active / reactive current reference I based on the grid voltage phase information. d_ref I q_ref Meanwhile, the MPPT algorithm needs to quickly adjust the operating point of the photovoltaic module so that V dc The dynamic values ​​in the grid-connected operation mode approach the reference range required for grid connection (e.g., relying on the matching of the maximum power point voltage and the grid voltage); then, based on the current reference value output by the power decoupling module and the V after MPPT adjustment... dc The initial control state for grid-connected operation is established; finally, a switching operation is performed: the phase angle is switched from the output of the virtual oscillator in grid-connected operation mode to the grid synchronization phase θ of the phase-locked loop (PLL) in grid-connected operation mode. grid The voltage reference value previously controlled by the AC voltage loop is replaced with the current reference value of the AC current loop (determined by the power decoupling module based on the grid voltage V). grid (Dynamically generated power commands) After the switching is completed, the grid-connected switch is closed, and the photovoltaic inverter switches from the off-grid mode dominated by the virtual oscillator to the grid-connected mode synchronized by the phase-locked loop. Although there is no BOOST circuit to assist, the output voltage V of the photovoltaic module can still be achieved through the coordinated control of the MPPT algorithm and the power decoupling module. dc Rapid matching with grid voltage ensures stable injection of grid-connected current.

[0188] like Figure 3 As shown, the virtual oscillator is mainly controlled through a virtual oscillator control loop. This control loop controls the active and reactive power of the grid-connected photovoltaic inverter, and its input is the output P of the DC bus voltage control loop. ref The signals are: active power setpoint signal, reactive power setpoint signal, real-time active power calculation signal P, and real-time reactive power calculation signal Q; the output is the AC voltage setpoint signal V. d ref V q ref .

[0189] The calculation formula for the virtual oscillator control loop is as follows:

[0190]

[0191] Among them, V ref To provide the amplitude for the inverter voltage measurement, ω nom For system rating

[0192] Angular frequency, usually taken as ω nom =2*π*50, k v =V nom =V ac rate V ac rate To measure the rated grid voltage for AC.

[0193] V d_ref =∑V ref

[0194] V q_ref =0

[0195] P and Q represent instantaneous active power and instantaneous reactive power, respectively, and are calculated as follows.

[0196] P = V d I d +V q I q

[0197] Q = -V d I q +V q I d .

[0198] k v —Voltage gain coefficient, usually taken as the rated mains voltage V nom ;

[0199] k—current gain coefficient, S n This is the rated apparent power.

[0200] P ref —Active power given, also known as active power reference.

[0201] Q ref —Reactive power given, also known as reactive power reference.

[0202] ξ—velocity constant.

[0203] For example, the virtual oscillator control loop can dynamically adjust the output voltage according to real-time power changes to achieve grid connection stability.

[0204] Additionally, to obtain the amplitude and phase of the virtual oscillator, if V is known... d and V q Then, the formula for calculating the amplitude A can also be used as follows:

[0205]

[0206] The formula for calculating the phase angle θ is as follows:

[0207] θ = arctan2(V q V d ).

[0208] V d (Direct-axis voltage): refers to the voltage component along the direct axis (D-axis) in the synchronous coordinate system; V q (Cross-axis voltage): refers to the voltage component along the cross-axis (Q-axis) in the synchronous coordinate system.

[0209] This embodiment proposes an intelligent switching method for photovoltaic inverters based on virtual oscillators between grid-connected and grid-connected operation modes. It encompasses multiple steps and control modules, specifically including collecting grid parameters and the current operating mode, determining the next operating mode (grid-connected or grid-connected) based on preset parameter thresholds and status judgments, and then implementing a smooth transition according to switching requirements. For the switch from grid-connected to grid-connected, initial conditions are first established by assigning a DQ-axis current, then the AC voltage loop and virtual oscillator are enabled, and power decoupling is disabled to gradually complete the switch. Conversely, if the initial conditions are not met, the virtual oscillator is disabled, and power decoupling control is initiated to ensure a smooth transition between the two modes. Figure 2 and Figure 3 Corresponding to the two-stage and single-stage grid-connected control structures, the former achieves fine adjustment through BOOST voltage loop, BOOST current loop, DC voltage loop and multi-loop coordination, and is suitable for high-power scenarios; the latter does not require, or has no, BOOST loop, has a simple structure, responds quickly, and is suitable for small or fast switching applications. Figure 4 and Figure 5 This demonstrates two-stage and single-stage grid control schemes. The former achieves stable grid construction through BOOST boosting, DC voltage control, virtual synchronization, and current regulation, while the latter employs a direct connection, simplified regulation, and rapid switching mechanism, with a key focus on introducing a current cross-switching module to enhance the flexibility of mode switching. Overall, this control strategy, combining multi-loop coordination, smooth switching, and intelligent judgment, effectively ensures the rapid and safe transition of photovoltaic inverters between different operating modes, improves system stability, regulation capability, and operating efficiency, and meets the intelligent and high-reliability energy management requirements of future smart microgrid systems.

[0210] Example 2:

[0211] like Figure 6 As shown, this embodiment provides a control device for the operating mode of a photovoltaic inverter, the device comprising:

[0212] The acquisition unit 10 is used to acquire the current grid parameters and the current operating mode of the photovoltaic inverter.

[0213] The determining unit 20, connected to the acquiring unit 10, is used to determine the next operating mode of the photovoltaic inverter based on the grid parameters and the current operating mode.

[0214] The detection unit 30 is connected to the acquisition unit 10 and the determination unit 20 respectively, and is used to detect the current operating mode and the next operating mode;

[0215] The first control unit 40 is connected to the detection unit 30. When the detection unit detects that the current operating mode is grid-following operating mode and the next operating mode is grid-connecting operating mode, it controls the photovoltaic inverter to switch from grid-following operating mode to grid-connecting operating mode through a virtual oscillator, and controls the photovoltaic inverter to operate according to the grid-connecting operating mode.

[0216] The second control unit 50 is connected to the detection unit 30. When the detection unit detects that the current operating mode is grid-connected operating mode and the next operating mode is grid-following operating mode, the control unit 50 controls the photovoltaic inverter to switch from grid-connected operating mode to grid-following operating mode through a virtual oscillator, and controls the photovoltaic inverter to operate in grid-following operating mode.

[0217] As one specific implementation, the determining unit 20 includes:

[0218] The first determining unit, connected to the acquiring unit, is used to determine the next operating mode of the photovoltaic inverter as the grid-following operating mode when the grid parameters are within the preset parameter threshold range and the current operating mode is the grid-following operating mode.

[0219] The second determining unit, connected to the acquiring unit, is used to determine the next operating mode of the photovoltaic inverter as the grid-connected operating mode when the grid parameters are not within the preset parameter threshold range and the current operating mode is the grid-connected operating mode.

[0220] The third determining unit, connected to the acquiring unit, is used to determine that the next operating mode of the photovoltaic inverter is still the grid-connected operating mode when the grid parameters are within the preset parameter threshold range and the current operating mode is the grid-connected operating mode.

[0221] The fourth determining unit, connected to the acquiring unit, is used to determine the next operating mode of the photovoltaic inverter as the grid-connected operating mode when the grid parameters are not within the preset parameter threshold range and the current operating mode is the grid-connected operating mode.

[0222] The apparatus in this embodiment is capable of performing the method in Embodiment 1.

[0223] Example 3:

[0224] like Figure 7As shown, this embodiment provides an electronic device, which includes a memory 200 and a processor 100. The memory 200 stores a computer program. When the processor 100 runs the computer program stored in the memory 200, the processor 100 executes the control method for the photovoltaic inverter operating mode according to Embodiment 1.

[0225] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A control method for the operating mode of a photovoltaic inverter, characterized in that, The method includes the following steps: Obtain the current grid parameters; and obtain the current operating mode of the photovoltaic inverter; Based on the grid parameters and the current operating mode, determine the next operating mode of the photovoltaic inverter; If the current operating mode is grid-following operating mode and the next operating mode is grid-building operating mode, then the photovoltaic inverter is controlled to switch from grid-following operating mode to grid-building operating mode through a virtual oscillator, and the photovoltaic inverter is controlled to operate according to the grid-building operating mode. If the current operating mode is the grid-connected operating mode and the next operating mode is the grid-following operating mode, then the photovoltaic inverter is controlled to switch from the grid-connected operating mode to the grid-following operating mode through the virtual oscillator, and the photovoltaic inverter is controlled to operate according to the grid-following operating mode.

2. The control method for the operating mode of a photovoltaic inverter according to claim 1, characterized in that, The step of determining the next operating mode of the photovoltaic inverter based on the grid parameters and the current operating mode specifically includes: If the grid parameters are within the preset parameter threshold range and the current operating mode is the grid-following operating mode, then the next operating mode of the photovoltaic inverter is determined to be the grid-following operating mode. If the grid parameters are not within the preset parameter threshold range and the current operating mode is the grid-connected operating mode, then the next operating mode of the photovoltaic inverter is determined to be the grid-connected operating mode. If the grid parameters are within the preset parameter threshold range and the current operating mode is the grid-connected operating mode, then the next operating mode of the photovoltaic inverter is determined to be the grid-connected operating mode. If the grid parameters are not within the preset parameter threshold range and the current operating mode is the grid-connected operating mode, then the next operating mode of the photovoltaic inverter is determined to be the grid-connected operating mode.

3. The control method for the operating mode of a photovoltaic inverter according to claim 1 or 2, characterized in that, The step of controlling the photovoltaic inverter to switch from grid-connected operation mode to grid-connected operation mode via a virtual oscillator specifically includes: Obtain the initial conditions for the network operation mode; Based on the initial conditions of the network operation mode, the AC voltage loop is enabled by a virtual oscillator; Based on the AC voltage loop, the initial control state of the network operation mode is obtained; Based on the initial control state of the network construction operation mode, the switch from the network following operation mode to the network construction operation mode is executed through a virtual oscillator.

4. The control method for the operating mode of a photovoltaic inverter according to claim 3, characterized in that, The initial conditions for obtaining the network operation mode specifically include: The DQ axis components of the current grid-connected current are assigned to the integral term of the PI controller in the AC voltage loop to obtain the initial conditions for the grid operation mode. The process of obtaining the initial control state of the network operation mode based on the AC voltage loop specifically includes: Based on the voltage reference signal provided by the AC voltage loop, a virtual oscillator loop anti-saturation processing is performed to obtain the anti-saturation processing result; Based on the anti-saturation processing results, the virtual oscillator control loop is enabled and the power decoupling module is disabled to obtain the initial control state of the network operation mode.

5. The control method for the operating mode of a photovoltaic inverter according to claim 3, characterized in that, The switching from network-following operation mode to network-building operation mode via a virtual oscillator specifically includes: Switch the phase angle from the phase angle output of the phase-locked loop to the phase angle output of the virtual oscillator; and, Switch the AC current from the current output of the power decoupling module to the current output of the AC voltage loop; The phase angle output of the phase-locked loop and the current output of the power decoupling module are both outputs in grid-following operation mode; the phase angle output of the virtual oscillator and the current output of the AC voltage loop are both outputs in grid-connected operation mode. The current output of the power decoupling module includes I d_ref_gfl and I q_ref_gfl The current output of the AC voltage loop includes I. d_ref_gfm I q_ref_gfm ; I d_ref_gfl This indicates the reference value of the DC component current in grid-connected operation mode; I q_ref_gfl This indicates the reference value of the cross component current in grid-connected operation mode; I d_ref_gfm This indicates the reference value of the DC component current under the grid-connected operation mode; I q_ref_gfm This indicates the reference value of the cross component current in the network operation mode.

6. The control method for the operating mode of a photovoltaic inverter according to claim 1 or 2, characterized in that, The step of controlling the photovoltaic inverter to switch from grid-connected operation mode to grid-following operation mode via a virtual oscillator specifically includes: Release the control logic that controls the network operation mode to obtain the initial conditions for the network operation mode; The control logic release in the network operation mode includes: disabling the AC voltage loop module and controlling the AC voltage loop to stop calculation; and disabling the virtual oscillator control loop module and controlling the virtual oscillator loop to stop calculation. Based on the initial conditions of the grid-following operation mode, the power decoupling module is enabled by a virtual oscillator and controlled to start calculation, thereby obtaining the initial control state of the grid-following operation mode. Based on the initial control state of the network-following operation mode, the switching from the network-building operation mode to the network-following operation mode is performed through a virtual oscillator.

7. The control method for the operating mode of a photovoltaic inverter according to claim 6, characterized in that, The switching from network construction mode to network following mode via a virtual oscillator specifically includes: Switch the phase angle from the phase angle output of the virtual oscillator to the phase angle output of the phase-locked loop; and, Switch the AC current from the current output of the AC voltage loop to the current output of the power decoupling module; The phase angle output of the phase-locked loop and the current output of the power decoupling module are both outputs in grid-following operation mode; the phase angle output of the virtual oscillator and the current output of the AC voltage loop are both outputs in grid-connected operation mode. The current output of the power decoupling module includes I d_ref_gfl and I q_ref_gfl The current output of the AC voltage loop includes I. d_ref_gfm I q_ref_gfm ; I d_ref_gfl This indicates the reference value of the DC component current in grid-connected operation mode; I q_ref_gfl This indicates the reference value of the cross component current in grid-connected operation mode; I d_ref_gfm This indicates the reference value of the DC component current under the grid-connected operation mode; I q_ref_gfm This indicates the reference value of the cross component current in the network operation mode.

8. A control device for the operating mode of a photovoltaic inverter, characterized in that, include: The acquisition unit is used to acquire the current grid parameters and the current operating mode of the photovoltaic inverter. A determining unit, connected to the acquiring unit, is used to determine the next operating mode of the photovoltaic inverter based on the grid parameters and the current operating mode; A detection unit, connected to the acquisition unit and the determination unit respectively, is used to detect the current operating mode and the next operating mode; The first control unit, connected to the detection unit, is used to control the photovoltaic inverter to switch from the grid-following operation mode to the grid-building operation mode via a virtual oscillator when the detection unit detects that the current operation mode is the grid-following operation mode and the next operation mode is the grid-building operation mode, and to control the photovoltaic inverter to operate according to the grid-building operation mode. The second control unit, connected to the detection unit, is used to control the photovoltaic inverter to switch from the grid-connected operation mode to the grid-connected operation mode via a virtual oscillator when the detection unit detects that the current operation mode is the grid-connected operation mode and the next operation mode is the grid-following operation mode, and to control the photovoltaic inverter to operate according to the grid-following operation mode.

9. The control device for the operation mode of a photovoltaic inverter according to claim 8, characterized in that, The determining unit includes: The first determining unit, connected to the acquiring unit, is used to determine the next operating mode of the photovoltaic inverter as the grid-following operating mode when the grid parameters are within a preset parameter threshold range and the current operating mode is the grid-following operating mode. The second determining unit, connected to the acquiring unit, is used to determine the next operating mode of the photovoltaic inverter as the grid-connected operating mode when the grid parameters are not within the preset parameter threshold range and the current operating mode is the grid-connected operating mode. The third determining unit, connected to the acquiring unit, is used to determine that the next operating mode of the photovoltaic inverter is still the grid-connected operating mode when the grid parameters are within the preset parameter threshold range and the current operating mode is the grid-connected operating mode. The fourth determining unit, connected to the acquiring unit, is used to determine the next operating mode of the photovoltaic inverter as the grid-connected operating mode when the grid parameters are not within the preset parameter threshold range and the current operating mode is the grid-connected operating mode.

10. An electronic device, characterized in that, It includes a memory and a processor, wherein the memory stores a computer program, and when the processor runs the computer program stored in the memory, the processor executes the operating mode control method according to any one of claims 1 to 7.

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