A diesel-storage hybrid overload prevention system, device and medium based on grid-connected inverter

Abstract

The present invention provides a diesel-storage hybrid overload prevention system, equipment and medium based on a grid-forming inverter. The pre-synchronization module realizes seamless switching between VSG mode and PQ mode based on dynamic voltage amplitude matching, phase-locked loop frequency synchronization and phase real-time alignment technology; the hardware current limiting module adopts high-speed current monitoring and hardware-level protection logic to cut off overcurrent pulses in real time to prevent power devices from failing due to transient impact; the power suppression module optimizes the power distribution between diesel generator and energy storage by real-time determination of overload threshold and steady-state recovery conditions; the logic determination module coordinates the dynamic frequency modulation of diesel generator and switching of energy storage mode. When the load suddenly changes, the diesel generator takes the priority to bear the transient power difference, and the energy storage is seamlessly switched to the grid-forming mode after the system recovers to steady state; this system optimizes the problems of transient overload and mode switching instability of the diesel-storage system through full-link collaborative design of software and hardware, thereby improving the stability and energy efficiency of the diesel-storage hybrid system.

Description

Technical Field

[0001] The present invention relates to the field of diesel-storage hybrid power, and more specifically, to a diesel-storage hybrid power overload prevention system, equipment and medium based on a grid-type inverter. Background Art

[0002] In current diesel-storage hybrid systems, the coordinated control of the inverter and diesel generator primarily relies on the PQ current source mode and the grid-type VSG control mode. In the PQ mode, the power source is controlled to output specific active power (P) and reactive power (Q), achieving power control by manipulating the magnitude and phase of the output current. The grid-type VSG (Virtual Synchronous Generator) mode simulates the operating characteristics of a traditional synchronous generator, controlling the output voltage, frequency, and power by manipulating a virtual rotor's equations of motion.

[0003] The PQ mode relies on a phase-locked loop to track the phase, making it susceptible to grid interference in weak grid conditions, leading to phase errors and power angle instability. It lacks active frequency and voltage regulation capabilities, relying on diesel generators to compensate for power shortfalls when the load suddenly changes, resulting in a delayed dynamic response. The current limiting mechanism is insufficient, making overload conditions prone to voltage drops and system collapse.

[0004] In the VSG mode, the virtual inertia does not match the mechanical inertia of the diesel generator, resulting in energy storage overload after the frequency regulation capacity is exhausted. The reactive power droop characteristic conflicts with the diesel generator regulation coefficient, causing reactive power distribution imbalance and stator overload risks. The economic optimization strategy weakens the transient load capacity, exacerbating system vulnerability.

[0005] Furthermore, both solutions suffer from power oscillations and transient instability during mode switching, and lack hardware-level overload protection, making them difficult to handle in short-circuit or high-impact load scenarios. Therefore, a coordinated control solution that integrates hardware protection, dynamic frequency modulation, and seamless switching is urgently needed to improve the stability and energy efficiency of diesel-storage hybrid systems. Summary of the Invention

[0006] In light of the above issues, the present invention aims to provide a diesel-storage hybrid overload prevention system, device, and medium based on a grid-connected inverter. This system utilizes a pre-synchronization module to achieve seamless switching between VSG and PQ modes; a hardware current limiting module to prevent power device failure due to transient surges; a power suppression module to optimize power distribution between the diesel generator and energy storage; and a logic decision module to coordinate dynamic frequency modulation of the diesel generator with energy storage mode switching. Through a comprehensive hardware and software collaborative design, this invention mitigates transient overload and mode switching instability issues in the diesel-storage hybrid system, thereby improving the stability and energy efficiency of the system.

[0007] A first aspect of the present invention provides a diesel-storage hybrid overload prevention system based on a grid-type inverter, the system comprising:

[0008] The pre-synchronization module is used to achieve seamless switching between VSG mode and PQ mode by dynamically matching the grid voltage amplitude information, frequency information and phase information;

[0009] The hardware current limiting module, based on real-time current monitoring and hardware-level protection mechanism, cuts off the overcurrent pulse when it is judged to be in overcurrent state;

[0010] The power suppression module is used to determine the overload threshold and steady-state recovery conditions based on frequency and power information, and adjust the distribution of energy storage power and diesel generator power;

[0011] The logic judgment module is used to coordinate the switching between the dynamic frequency regulation of the diesel generator and the grid mode. When the load suddenly changes, the diesel generator will take the priority to bear the transient power difference. After the system returns to steady state, it will switch from PQ mode to VSG mode.

[0012] In this solution, the pre-synchronization module specifically includes:

[0013] The voltage matching unit adjusts the output voltage amplitude information through closed-loop control so that the deviation between the voltage amplitude information and the target grid voltage amplitude is less than a preset voltage deviation threshold;

[0014] The frequency synchronization unit measures the grid frequency information in real time through phase-locked loop technology, and dynamically corrects the internal reference frequency information of the VSG according to the grid frequency information, so that the deviation between the grid frequency information and the reference frequency information is less than the preset frequency deviation threshold;

[0015] The phase alignment unit is used to detect the grid phase information in real time and adjust the output phase angle of the inverter through the first PID controller.

[0016] In this solution, the hardware current limiting module specifically includes:

[0017] a current acquisition unit, which obtains output current information of the inverter based on a high-precision current sensor at a preset first sampling frequency, wherein the high-precision current sensor includes a Hall sensor or a shunt resistor circuit;

[0018] a high-speed comparison unit, which compares the output current information with a preset reference current threshold at a high speed according to a preset first comparison frequency through a hardware comparator circuit to obtain current comparison information;

[0019] A hardware protection unit triggers hardware protection logic based on the current comparison information, wherein the hardware protection logic is desaturation protection; if the output current information is greater than the reference current threshold, the hardware protection logic is triggered according to a preset first switching cycle to shut down the power device.

[0020] In this solution, the hardware current limiting module also includes:

[0021] Self-recovery unit, performs self-recovery steps:

[0022] In the next first switching cycle, turning on the power device;

[0023] Determining whether the output current information is greater than the reference current threshold;

[0024] If so, the wave-by-wave current limiting operation mode is triggered;

[0025] If not, the power device remains turned on.

[0026] In this solution, the power suppression module specifically includes:

[0027] an overload determination unit, for determining whether the inverter is in an overload state based on output voltage information and output current information of the inverter;

[0028] The steady-state recovery unit determines whether the inverter output has recovered to a steady state based on the output frequency information of the inverter.

[0029] In this solution, the overload determination unit performs an overload determination process, specifically:

[0030] Obtaining output power information according to the output voltage amplitude information and the output current information;

[0031] According to the output power information and the preset rated power information, power ratio information is obtained by using a preset sliding window averaging algorithm;

[0032] Recording the number of consecutive sampling times when the power ratio information exceeds a preset power ratio threshold range;

[0033] When the number of consecutive sampling times exceeds a preset threshold, current limiting protection is triggered to reduce the output current information of the inverter.

[0034] In this solution, the steady-state recovery unit executes a steady-state recovery process, specifically:

[0035] Processing the output frequency information based on a preset low-pass filter to obtain filtered frequency information;

[0036] Get VSG internal reference frequency information;

[0037] Obtaining a steady-state frequency dead zone range according to the reference frequency information;

[0038] Determining whether the filtering frequency information is within the steady-state frequency dead zone;

[0039] If yes, the grid mode is switched to VSG mode.

[0040] In this solution, the logic determination module specifically includes:

[0041] A diesel engine regulating unit, configured to adjust the diesel engine fuel valve opening through a second PID controller according to the inverter output frequency information;

[0042] The grid mode switching unit switches the grid mode to the PQ mode or the VSG mode based on the output frequency change rate and the output power deviation of the inverter.

[0043] A second aspect of the present invention provides an electronic device, which includes a processor, a memory, a communication interface and a communication bus, wherein the processor, the communication interface and the memory communicate with each other through the communication bus; the memory is used to store computer programs; the processor is used to implement the operating steps of the diesel-storage hybrid anti-overload system based on the grid-type inverter as described in any of the above items when executing the program stored in the memory.

[0044] The third aspect of the present invention provides a computer-readable storage medium, which includes a diesel-storage hybrid anti-overload system program based on a grid-type inverter. When the diesel-storage hybrid anti-overload system program based on a grid-type inverter is executed by a processor, it implements the steps of the diesel-storage hybrid anti-overload system based on a grid-type inverter as described in any one of the above items.

[0045] The present invention provides a diesel-storage hybrid overload prevention system, equipment and medium based on a grid-forming inverter. The pre-synchronization module realizes seamless switching between VSG mode and PQ mode based on dynamic voltage amplitude matching, phase-locked loop frequency synchronization and phase real-time alignment technology; the hardware current limiting module adopts high-speed current monitoring and hardware-level protection logic to cut off overcurrent pulses in real time to prevent power devices from failing due to transient impact; the power suppression module optimizes the power distribution between diesel generator and energy storage by real-time determination of overload threshold and steady-state recovery conditions; the logic determination module coordinates the dynamic frequency modulation of diesel generator and switching of energy storage mode. When the load suddenly changes, the diesel generator takes the priority to bear the transient power difference, and the energy storage is seamlessly switched to the grid-forming mode after the system recovers to steady state; this system optimizes the problems of transient overload and mode switching instability of the diesel-storage system through full-link collaborative design of software and hardware, thereby improving the stability and energy efficiency of the diesel-storage hybrid system. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope.

[0047] Figure 1 The present invention shows a schematic structural diagram of a diesel-storage hybrid overload prevention system based on a grid-type inverter;

[0048] Figure 2 It shows a schematic diagram of the structure of the synchronization module provided by an embodiment of the present invention;

[0049] Figure 3 It shows a schematic structural diagram of a hardware current limiting module provided by an embodiment of the present invention;

[0050] Figure 4 It shows a schematic structural diagram of a power suppression module provided by an embodiment of the present invention;

[0051] Figure 5 A flowchart showing overload determination by an overload determination unit provided by an embodiment of the present invention is shown;

[0052] Figure 6 A flowchart showing steady-state recovery performed by a steady-state recovery unit provided by an embodiment of the present invention is shown;

[0053] Figure 7 A diesel-storage hybrid overload prevention device based on a grid-type inverter provided by an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0054] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0055] Unless otherwise defined, all terms (including technical and scientific terms) used in the embodiments of the present invention have the same meaning as commonly understood by those skilled in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined in this manner in the embodiments of the present invention.

[0056] The words "first", "second" and similar terms used in the embodiments of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "one", "an" or "the" do not indicate a quantity limitation, but rather indicate the existence of at least one. Similarly, words such as "include" or "comprise" mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The steps before or after the method of the embodiment of the present invention do not necessarily have to be performed in exact order. On the contrary, the various steps may be processed in reverse order or simultaneously. At the same time, other operations may be added to these processes, or one or more steps may be removed from these processes.

[0057] In addition, the functional modules in the various embodiments of the present invention may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

[0058] Figure 1 The schematic diagram of the structure of a diesel-storage hybrid anti-overload system based on a grid-type inverter of the present invention is shown.

[0059] like Figure 1 As shown, the first aspect of the present invention discloses a diesel-storage hybrid overload prevention system 10 based on a grid-type inverter, the system comprising:

[0060] The pre-synchronization module 101 is used to achieve seamless switching between the VSG mode and the PQ mode by dynamically matching the grid voltage amplitude information, frequency information and phase information;

[0061] The hardware current limiting module 102, based on real-time current monitoring and hardware-level protection mechanism, cuts off the overcurrent pulse when it is determined to be in an overcurrent state;

[0062] The power suppression module 103 is used to determine the overload threshold and steady-state recovery conditions based on the frequency information and power information, and adjust the distribution of energy storage power and diesel generator power;

[0063] The logic decision module 104 is used to coordinate the switching between the dynamic frequency regulation of the diesel generator and the grid mode. When the load suddenly changes, the diesel generator takes the priority to bear the transient power difference. After the system returns to a steady state, the PQ mode is switched to the VSG mode.

[0064] It should be noted that in VSG (Virtual Synchronous Generator) grid-connected technology, the pre-synchronization module is primarily used before the inverter to ensure that the inverter's output voltage, frequency, and phase precisely match grid parameters, thereby enabling seamless switching between VSG and PQ modes—in other words, smooth and seamless grid-connected operation. The hardware current limiting module is a high-speed current protection mechanism based on hardware circuitry. It monitors the output current in real time during each inverter switching cycle. When the current exceeds a preset threshold, it immediately limits the current amplitude through hardware logic to prevent damage to power devices due to overcurrent. The power suppression module triggers current limiting protection when the inverter's output power exceeds the rated power, indicating a power overload. When the inverter's output frequency determines that steady-state has been restored, it switches to VSG mode, dynamically allocating energy storage power to the diesel generator. Dynamic power calculation and filtering algorithms are used to avoid misjudgments, and steady-state recovery logic is employed to enhance system automation. The logic judgment module dynamically adjusts the diesel generator's fuel valve opening based on the inverter's output status, automatically switching to grid mode. This ensures load supply while reducing energy consumption, balancing system power supply stability and energy efficiency.

[0065] Figure 2 It shows a schematic structural diagram of a synchronization module provided by an embodiment of the present invention.

[0066] According to an embodiment of the present invention, Figure 2 As shown, the pre-synchronization module 101 specifically includes:

[0067] The voltage matching unit 201 adjusts the output voltage amplitude information through closed-loop control so that the deviation between the voltage amplitude information and the target grid voltage amplitude is less than a preset voltage deviation threshold;

[0068] The frequency synchronization unit 202 measures the grid frequency information in real time through the phase-locked loop technology, and dynamically modifies the VSG internal reference frequency information according to the grid frequency information, so that the deviation between the grid frequency information and the reference frequency information is less than a preset frequency deviation threshold;

[0069] The phase alignment unit 203 is configured to detect grid phase information in real time and adjust the output phase angle of the inverter through a first PID controller.

[0070] It should be noted that the voltage matching unit is used to adjust the amplitude of the inverter output voltage. Based on the difference between the output voltage replica and the target grid voltage amplitude, a closed-loop control algorithm is used to bring the output voltage amplitude closer to the target grid voltage. This closed-loop regulation is a PI regulation algorithm. The frequency synchronization unit is used to adjust the frequency of the inverter output voltage. Using phase-locked loop (PLL) technology, it tracks and measures the grid frequency in real time, dynamically corrects the VSG internal reference frequency based on the grid frequency, and then adjusts the inverter output voltage frequency based on the reference frequency, thereby bringing the inverter output voltage frequency closer to the grid frequency. The phase alignment unit is used to adjust the phase angle of the inverter output voltage. Based on the deviation between the real-time measured grid phase angle and the inverter output voltage phase angle, the control variable of the first PID controller is used to adjust the inverter output based on the control variable, so that the output voltage phase angle approaches the grid phase angle. In one embodiment, the first PID controller uses a PI regulation algorithm.

[0071] Figure 3 It shows a structural diagram of a hardware current limiting module provided by an embodiment of the present invention.

[0072] According to an embodiment of the present invention, Figure 3 As shown, the hardware current limiting module 102 specifically includes:

[0073] The current acquisition unit 301 obtains output current information of the inverter based on a high-precision current sensor according to a preset first sampling frequency, wherein the high-precision current sensor includes a Hall sensor or a shunt resistor circuit;

[0074] The high-speed comparison unit 302 compares the output current information with a preset reference current threshold at a high speed according to a preset first comparison frequency through a hardware comparator circuit to obtain current comparison information;

[0075] The hardware protection unit 303 triggers the hardware protection logic based on the current comparison information, wherein the hardware protection logic is desaturation protection; if the output current information is greater than the reference current threshold, the hardware protection logic is triggered according to a preset first switching cycle to shut down the power device.

[0076] It should be noted that the current acquisition unit collects the inverter output current signal, which is then conditioned by a differential amplifier circuit and input to the high-speed comparator circuit of the high-speed comparison unit. The comparison result is then input to the hardware protection unit. The current acquisition unit uses a high-precision current sensor, such as a Hall effect sensor or a shunt resistor circuit, to detect the inverter output current based on a preset current acquisition frequency. The high-speed comparison unit includes a hardware comparator circuit and a trigger circuit. Based on a preset comparison execution frequency, the high-speed comparison unit compares the amplitude of the inverter current signal with a preset reference current threshold signal to obtain current comparison information. In practical applications, the first sampling frequency and the first comparison frequency are the same. The hardware protection unit reads the current comparison result based on the switching cycle. If the output current information is greater than the reference current threshold, indicating that the inverter output current is too high and an overcurrent condition exists, the desaturation protection (DESAT) of the driver chip is triggered, immediately shutting down the power device during the current switching cycle to prevent further current increase and damage to the device, thereby improving system operational safety.

[0077] According to an embodiment of the present invention, the hardware current limiting module further includes:

[0078] Self-recovery unit, performs self-recovery steps:

[0079] In the next first switching cycle, turning on the power device;

[0080] Determining whether the output current information is greater than the reference current threshold;

[0081] If so, the wave-by-wave current limiting operation mode is triggered;

[0082] If not, the power device remains turned on.

[0083] It should be noted that this embodiment provides a self-recovery mechanism. After a power device is shut down, the self-recovery unit attempts to turn it back on in the next switching cycle. If the current returns to normal, the system continues to operate. If the overcurrent persists, a cycle-by-cycle current limiting cycle is triggered until the fault is resolved. This further improves the automation level of system operation. The cycle-by-cycle current limiting operation mode performs a current limiting-recovery cycle based on the wave transmission cycle.

[0084] Figure 4 A schematic structural diagram of a power suppression module provided by an embodiment of the present invention is shown.

[0085] According to an embodiment of the present invention, Figure 4 As shown, the power suppression module 103 specifically includes:

[0086] An overload determination unit 401 determines whether the inverter is in an overload state based on output voltage information and output current information of the inverter;

[0087] The steady-state recovery unit 402 determines whether the inverter output has recovered to a steady state based on the output frequency information of the inverter.

[0088] It should be noted that the overload determination unit is used to determine whether the inverter's transient output power is too high. If an overload condition is detected, current limiting protection is triggered, reducing the inverter's output current and, therefore, power, to protect the system. The steady-state recovery unit, based on the inverter's adjusted output frequency and filtering out high-frequency noise, determines whether the filtered frequency is within the set steady-state frequency range. If so, the inverter system has recovered steady-state and the grid mode is switched to VSG mode. In VSG mode, energy storage power and diesel generator power are dynamically allocated based on the inverter's operating status.

[0089] Figure 5 The flowchart of the overload determination unit according to the embodiment of the present invention is shown.

[0090] According to an embodiment of the present invention, Figure 5 As shown, the overload determination unit performs an overload determination process, specifically:

[0091] S502, obtaining output power information according to the output voltage amplitude information and the output current information;

[0092] S504, obtaining power ratio information based on the output power information and the preset rated power information by using a preset sliding window averaging algorithm;

[0093] S506, recording the number of consecutive sampling times that the power ratio information exceeds a preset power ratio threshold range;

[0094] S508: When the number of consecutive sampling times exceeds a preset threshold, current limiting protection is triggered to reduce the output current information of the inverter.

[0095] It should be noted that this embodiment provides an overload determination process, which determines whether the inverter is overloaded based on the output power of the inverter. First, based on the instantaneous output voltage amplitude and output current of the inverter, the instantaneous output power is obtained. Secondly, based on at least 2 instantaneous output powers, based on the preset sliding window averaging algorithm, the instantaneous average power is obtained to eliminate noise disturbances; then, the power ratio is obtained by performing a ratio operation based on the instantaneous average power and the preset rated power. Then, the number of consecutive sampling cycles in which the power ratio continuously exceeds the preset power ratio threshold is recorded. If the number of consecutive sampling cycles exceeds the preset number threshold, it indicates that the output of the inverter is in a stable overload state. At this time, the current limiting is triggered and switched to the PQ mode, and the purpose of protecting the inverter system is achieved by reducing the output current of the inverter.

[0096] Figure 6 A flow chart showing the steady-state recovery performed by the steady-state recovery unit provided by an embodiment of the present invention is shown.

[0097] According to an embodiment of the present invention, Figure 6 As shown, the steady-state recovery unit executes the steady-state recovery process, specifically:

[0098] S602, processing the output frequency information based on a preset low-pass filter to obtain filtered frequency information;

[0099] S604, obtaining VSG internal reference frequency information;

[0100] S606, obtaining a steady-state frequency dead zone range according to the reference frequency information;

[0101] S608, determining whether the filtering frequency information is within the steady-state frequency dead zone;

[0102] S610: If yes, switch the grid mode to the VSG mode.

[0103] It should be noted that this embodiment provides a steady-state recovery process, which determines whether the inverter system has recovered to a steady state based on the frequency of the inverter output voltage. First, based on a preset low-pass filter, including but not limited to a Butterworth low-pass filter, the frequency signal of the inverter output voltage is processed to obtain filtered frequency information to eliminate high-frequency noise. Then, according to the VSG internal reference frequency set by the frequency synchronization unit, the dead zone range of the steady-state frequency is determined; wherein the dead zone range indicates the output frequency allowed to float frequency range. Finally, when the filtered frequency information is within the steady-state frequency dead zone range, it indicates that the inverter system has recovered to a steady state. At this time, the grid mode is switched to the VSG mode.

[0104] According to an embodiment of the present invention, the logic determination module specifically includes:

[0105] A diesel engine regulating unit, configured to adjust the diesel engine fuel valve opening through a second PID controller according to the inverter output frequency information;

[0106] The grid mode switching unit switches the grid mode to the PQ mode or the VSG mode based on the output frequency change rate and the output power deviation of the inverter.

[0107] It should be noted that the diesel generator regulation unit dynamically adjusts the fuel valve opening based on the frequency deviation between the inverter output frequency and the VSG internal reference frequency via a second PID controller to adjust the diesel generator power. This second PID controller uses a fuzzy PID control algorithm. This dynamic adjustment of the diesel generator power ensures system power supply while improving energy efficiency. The grid mode switching unit switches the grid mode based on a weighted index calculated from the inverter's output frequency change rate and output power deviation. If this index exceeds a preset threshold, the system switches to PQ mode; otherwise, it switches to VSG mode.

[0108] It is worth mentioning that it also includes:

[0109] The dynamic correlation model coordinates the diesel engine fuel valve opening based on the virtual inertia parameters and damping coefficient of the VSG.

[0110] It should be noted that the diesel engine rotor inertia is measured in real time by a speed sensor and used to dynamically adjust the VSG's virtual inertia parameters. Frequency analysis is used to monitor the diesel engine system's oscillation amplitude in real time and adjust the VSG's damping coefficient. Based on the virtual inertia parameters and the damping coefficient, the diesel engine fuel valve opening is adjusted in tandem to optimize the system's damping characteristics and reduce the risk of instability.

[0111] It is worth mentioning that it also includes:

[0112] The feedforward control unit is used to detect load current information in real time, analyze the change trend of the load current information, and switch to the PQ mode and wave-by-wave current limiting operation mode based on the change trend.

[0113] It should be noted that in high-impact load scenarios, the inverter uses a feedforward control unit to detect the load current trend and derive the slope of change based on the load current derivative. If the slope exceeds a preset slope threshold, the inverter switches to PQ mode and uses wave-by-wave current limiting to improve shock load absorption, thereby enhancing system safety.

[0114] Figure 7 A flow chart showing the steady-state recovery performed by the steady-state recovery unit provided by an embodiment of the present invention is shown.

[0115] like Figure 7 As shown, the second aspect of the present invention provides an electronic device, which includes a processor 701, a memory 702, a communication interface 703 and a communication bus 704, wherein the processor, the communication interface and the memory communicate with each other through the communication bus; the memory is used to store computer programs; the processor is used to implement the operating steps of the diesel-storage hybrid anti-overload system based on the grid-type inverter as described in any one of the above items when executing the program stored in the memory.

[0116] The third aspect of the present invention provides a computer-readable storage medium, which includes a diesel-storage hybrid anti-overload system program based on a grid-type inverter. When the diesel-storage hybrid anti-overload system program based on a grid-type inverter is executed by a processor, it implements the steps of the diesel-storage hybrid anti-overload system based on a grid-type inverter as described in any one of the above items.

[0117] In summary, the present invention provides a diesel-storage hybrid overload prevention system, equipment and medium based on a grid-forming inverter. The pre-synchronization module realizes seamless switching between VSG mode and PQ mode based on dynamic voltage amplitude matching, phase-locked loop frequency synchronization and phase real-time alignment technology; the hardware current limiting module adopts high-speed current monitoring and hardware-level protection logic to cut off overcurrent pulses in real time to prevent power devices from failing due to transient impact; the power suppression module optimizes the power distribution between diesel generator and energy storage by real-time determination of overload threshold and steady-state recovery conditions; the logic determination module coordinates the dynamic frequency modulation of diesel generator and energy storage mode switching. When the load suddenly changes, the diesel generator takes priority to bear the transient power difference, and seamlessly switches the energy storage to the grid-forming mode after the system recovers to steady state; this system optimizes the problems of transient overload and mode switching instability of the diesel-storage system through full-link collaborative design of software and hardware, thereby improving the stability and energy efficiency of the diesel-storage hybrid system.

[0118] If the functions are implemented as software modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or the portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage media include various media capable of storing program code, such as USB flash drives, mobile hard drives, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical disks.

[0119] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A diesel-storage hybrid overload prevention system based on a grid-connected inverter, characterized in that: The system comprises: The pre-synchronization module is used to achieve seamless switching between VSG mode and PQ mode by dynamically matching the grid voltage amplitude information, frequency information and phase information; The hardware current limiting module, based on real-time current monitoring and hardware-level protection mechanism, cuts off the overcurrent pulse when it is judged to be in overcurrent state; The power suppression module is used to determine the overload threshold and steady-state recovery conditions based on frequency and power information, and adjust the distribution of energy storage power and diesel generator power; The logic decision module is used to coordinate the switching between the dynamic frequency regulation of the diesel generator and the grid mode. In the event of a sudden load change, the diesel generator will take the priority to bear the transient power difference. After the system returns to a steady state, it will switch from PQ mode to VSG mode. A feedforward control unit is used to detect load current information in real time, analyze the change trend of the load current information, and switch to the PQ mode and the wave-by-wave current limiting operation mode based on the change trend; The hardware current limiting module further includes a self-recovery unit that performs the following self-recovery steps: In the next first switching cycle, turning on the power device; Determine whether the output current information is greater than a reference current threshold; If so, the wave-by-wave current limiting operation mode is triggered; If not, the power device remains turned on.

2. The diesel-storage hybrid overload protection system based on a grid-connected inverter according to claim 1 is characterized in that: The pre-synchronization module specifically includes: The voltage matching unit adjusts the output voltage amplitude information through closed-loop control so that the deviation between the voltage amplitude information and the target grid voltage amplitude is less than a preset voltage deviation threshold; The frequency synchronization unit measures the grid frequency information in real time through phase-locked loop technology, and dynamically corrects the internal reference frequency information of the VSG according to the grid frequency information, so that the deviation between the grid frequency information and the reference frequency information is less than the preset frequency deviation threshold; The phase alignment unit is used to detect the grid phase information in real time and adjust the output phase angle of the inverter through the first PID controller.

3. The diesel-storage hybrid overload prevention system based on a grid-connected inverter according to claim 1 is characterized in that: The hardware current limiting module specifically includes: a current acquisition unit, which obtains output current information of the inverter based on a high-precision current sensor at a preset first sampling frequency, wherein the high-precision current sensor includes a Hall sensor or a shunt resistor circuit; a high-speed comparison unit, which compares the output current information with a preset reference current threshold at a high speed according to a preset first comparison frequency through a hardware comparator circuit to obtain current comparison information; A hardware protection unit triggers hardware protection logic based on the current comparison information, wherein the hardware protection logic is desaturation protection; if the output current information is greater than the reference current threshold, the hardware protection logic is triggered according to a preset first switching cycle to shut down the power device.

4. The diesel-storage hybrid overload prevention system based on a grid-connected inverter according to claim 1 is characterized in that: The power suppression module specifically includes: an overload determination unit, for determining whether the inverter is in an overload state based on output voltage information and output current information of the inverter; The steady-state recovery unit determines whether the inverter output has recovered to a steady state based on the output frequency information of the inverter.

5. The diesel-storage hybrid overload protection system based on a grid-connected inverter according to claim 4 is characterized in that: The overload determination unit performs an overload determination process, specifically: Obtaining output power information according to the output voltage amplitude information and the output current information; According to the output power information and the preset rated power information, power ratio information is obtained by using a preset sliding window averaging algorithm; Recording the number of consecutive sampling times when the power ratio information exceeds a preset power ratio threshold range; When the number of consecutive sampling times exceeds a preset threshold, current limiting protection is triggered to reduce the output current information of the inverter.

6. The diesel-storage hybrid overload prevention system based on a grid-connected inverter according to claim 4 is characterized in that: The steady-state recovery unit performs a steady-state recovery process, specifically: Processing the output frequency information based on a preset low-pass filter to obtain filtered frequency information; Get VSG internal reference frequency information; Obtaining a steady-state frequency dead zone range according to the reference frequency information; Determining whether the filtering frequency information is within the steady-state frequency dead zone; If yes, the grid mode is switched to VSG mode.

7. The diesel-storage hybrid overload prevention system based on a grid-connected inverter according to claim 1 is characterized in that: The logic determination module specifically includes: A diesel engine regulating unit, configured to adjust the diesel engine fuel valve opening through a second PID controller according to the inverter output frequency information; The grid mode switching unit switches the grid mode to the PQ mode or the VSG mode based on the output frequency change rate and the output power deviation of the inverter.

8. An electronic device, characterized in that: The system comprises a processor, a memory, a communication interface and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus; Memory for storing computer programs; The processor is configured to implement the operation steps of the diesel-storage hybrid overload protection system based on a grid-type inverter according to any one of claims 1 to 7 when executing the program stored in the memory.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: The computer-readable storage medium includes a diesel-storage hybrid anti-overload system program based on a grid-type inverter. When the diesel-storage hybrid anti-overload system program based on a grid-type inverter is executed by a processor, the operating steps of the diesel-storage hybrid anti-overload system based on a grid-type inverter are implemented as described in any one of claims 1 to 7.

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