Inverter ac current sensor fault judgment and control method and system

Abstract

The application provides an inverter AC current sensor fault judgment and control method and system, and belongs to the field of inverter fault detection and control. The main method process is as follows: firstly, a virtual impedance is set, then the current is reconstructed according to the virtual impedance, the collected AC voltage, the modulation voltage output by the control unit at the last moment, and the actual impedance; subsequently, the absolute value and the effective value of the residual current are calculated according to the collected AC current and the reconstructed current to perform fault logic judgment, the AC current control feedback signal is switched, or an output control shutdown signal is generated; if not shutdown, the impedance voltage and the control unit output control voltage signal are calculated, and the modulation voltage signal is generated by the difference between the two to control the inverter system. The current reconstruction method of the application does not need to accurately obtain the inductance equivalent resistance, can effectively reduce the current impact on the power grid or the load when the AC current sensor fails, realizes seamless and smooth protection, and has a clever algorithm design and high practicability.

Description

Technical Field

[0001] This invention belongs to the field of inverter fault detection and control, and particularly relates to a method and system for fault judgment and control of inverter AC current sensor. Background Technology

[0002] With the continuous growth of global electricity demand and the rapid development and widespread, high-penetration application of new energy technologies, inverters, as key power electronic devices, are widely used in the power sector. Therefore, the safe and stable operation of inverter equipment has a significant impact on improving the reliability of the entire power conversion system. The sensor units in the inverter, as inputs to control information, play a crucial role in the control and monitoring of the entire system. In particular, the AC current sensor not only affects the waveform quality of AC current and voltage but also plays a critical role in hardware overcurrent protection. When the AC sensor suddenly fails during inverter operation, errors in the control algorithm feedback can lead to distortion of the current waveform or even cause the inverter to overcurrent and explode.

[0003] Traditional solutions employ state observer methods, parameter estimation methods, and artificial intelligence methods to extract fault signals, diagnose and identify sensor faults. However, these methods suffer from complex algorithms and difficulties in engineering applications. Commonly used state observer methods typically require design based on inverter models, which necessitates high model accuracy. In reality, inverters experience dead-zone errors and nonlinear changes in inductor parameters during operation, leading to significant errors in the observed AC current. Consequently, under certain operating conditions, accurate inverter control and protection cannot be achieved. Summary of the Invention

[0004] To address the above problems, the first aspect of this invention provides a method for fault diagnosis and control of an inverter AC current sensor, comprising the following steps:

[0005] S1, Set the virtual impedance Z v ;

[0006] S2, acquire the AC voltage V collected by the voltage sampling circuit. g Simultaneously, the modulation voltage U output by the control unit at the previous moment is acquired. pwm_last The Z v V g U pwm_last Combined with actual impedance Z L The current is reconstructed using an AC current reconstruction algorithm to obtain the reconstructed current I. ac_cal ;

[0007] S3 performs AC sensor fault diagnosis and outputs corresponding control signals; first, it acquires the AC current I collected by the current sensor. acThe instantaneous value of the current residual is calculated, and the instantaneous value of the current residual is equal to the reconstructed current I. ac_cal With alternating current I ac The difference is used to obtain the absolute value I of the residual current. ac_dif With effective value I ac_dif_rms Then, using the absolute value I of the obtained residual current... ac_dif With effective value I ac_dif_rms Perform fault logic judgment, and generate AC current control feedback signal S based on the judgment result. con The system switches to S4; if a fault stop condition is triggered, a fault stop control signal S is output. W The system is directed to the control unit, which then controls the shutdown.

[0008] S4 controls the feedback signal S through the generated alternating current. con With the set virtual impedance Z v Calculate the impedance voltage U v Meanwhile, the control unit controls the feedback signal S based on the acquired AC current. con Generate the corresponding control voltage signal U pwm ;

[0009] S5, the control voltage signal U pwm With impedance voltage U v The difference is calculated by introducing the effect of impedance voltage drop into the control loop to obtain the modulated voltage signal U of the inverter. pwm_ref The PWM generation and driving circuit is based on the U pwm_ref The power switch is generated to drive the PWM signal to control the inverter system.

[0010] Preferably, the virtual impedance Z in S1 v The complex domain expression is:

[0011] Z v =L v s+R v

[0012] Where L v For virtual inductance, R v Here, S is the virtual resistance, and S is the complex frequency.

[0013] The actual impedance Z in S2 L The complex domain expression is:

[0014] Z L =Ls+R L

[0015] Where L is the AC filter inductance, R L Let L be the equivalent resistance of the inductor, and S be the complex frequency.

[0016] Preferably, the AC current reconstruction algorithm formula in S2 is:

[0017]

[0018] Where the virtual impedance Z v Relative to Z v +Z L The larger the proportion, the higher the reconstruction accuracy, which is affected by the actual impedance Z. L The smaller the impact.

[0019] Preferably, the specific process of fault logic judgment in S3 is as follows:

[0020] If I ac_dif If the upper limit threshold Thb is exceeded, a fault shutdown condition is triggered, and a fault shutdown control signal S is output. W The signal is sent to the control unit, which then controls the shutdown. If the upper limit threshold Thb is not exceeded but the lower limit threshold Tha is exceeded, an AC current control feedback signal S is sent. con The switch, at this time S con =I ac_cal If I ac_dif If the current is less than the lower threshold Tha, the AC current control feedback signal S will not be triggered. con The switch, at this time S con =I ac If the AC current control feedback signal S is triggered con After the switch, if the system runs for more than t1 during the AC current sensor fault period, it will trigger the fault shutdown condition and output the fault shutdown control signal S. W The system is directed to the control unit, which then controls the shutdown. If the running time does not exceed t1, the effective value of the current residual I is calculated. ac_dif_rms Judgment, I ac_dif_rms When the current is less than the upper limit threshold Thb and the duration is greater than t2, the control feedback signal of the AC current is restored to S. con =I ac .

[0021] Preferably, in step S4, the feedback signal S is controlled by the generated alternating current. con With the set virtual impedance Z v Calculate the impedance voltage U v The calculation formula is:

[0022] Uv=ZvScon

[0023] The above calculation formulas are based on Ohm's law for circuits.

[0024] A second aspect of the present invention provides an inverter AC current sensor fault diagnosis and control device, the device comprising at least one processor and at least one memory, the processor and the memory being coupled together; the memory storing a computer program; when the processor executes the computer program stored in the memory, the device implements the inverter AC current sensor fault diagnosis and control method as described in the first aspect.

[0025] A third aspect of the present invention provides a computer-readable storage medium storing a program or instructions that, when executed by a processor, cause a computer to perform the inverter AC current sensor fault diagnosis and control method as described in the first aspect.

[0026] The fourth aspect of the present invention provides a fault diagnosis and control system for an inverter AC current sensor, characterized in that: it includes the fault diagnosis and control device for an inverter AC current sensor as described in the second aspect, and also includes a current sensor, a voltage sampling circuit and a PWM generation and driving circuit, wherein the inverter is connected to the power grid or load through an AC filter inductor L.

[0027] The beneficial effects of this invention are:

[0028] 1. The AC current reconstruction method proposed in this invention does not require accurate acquisition of the equivalent resistance of the inductor, and the accuracy of the reconstructed AC current is minimally affected by the nonlinear changes in the inductor.

[0029] 2. The inverter AC sensor fault judgment and control method proposed in this invention can effectively reduce the current impact on the power grid or load when the AC current sensor fails, and achieve seamless and smooth protection.

[0030] 3. The inverter AC sensor fault diagnosis and control method proposed in this invention has an ingenious overall algorithm design. Compared with some existing algorithms, it has strong practical applicability and is more suitable for engineering applications. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the overall structure of the inverter AC current sensor fault diagnosis and control system of the present invention.

[0033] Figure 2This is a flowchart of the inverter AC current sensor fault diagnosis and control algorithm of the present invention.

[0034] Figure 3 This is a schematic diagram of the AC current waveform reconstructed by the AC current sensor when the equivalent inductance and resistance components of the inverter remain unchanged.

[0035] Figure 4 This is a schematic diagram of the AC current waveform reconstructed by the AC current sensor when the equivalent inductance of the inverter in this invention is attenuated by 50% and the resistance measurement error is 50%.

[0036] Figure 5 This is a schematic diagram of the reconstructed current and current residual when the AC current sensor of the inverter of the present invention experiences a short circuit fault.

[0037] Figure 6 This is a schematic diagram illustrating the change in inverter output current and the system protection process when a short-circuit fault occurs in the inverter AC current sensor of this invention.

[0038] Figure 7 This is a simplified structural block diagram of the inverter AC current sensor fault diagnosis and control device of the present invention. Detailed Implementation

[0039] Example 1:

[0040] This embodiment combines Figures 1 to 6 The present invention provides a further explanation of the inverter AC current sensor fault diagnosis and control method and system.

[0041] like Figure 1 As shown, to implement the inverter AC current sensor fault diagnosis and control method of the present invention, the system structure adopted includes a voltage sampling circuit, a PWM generation and driving circuit, and the most important fault diagnosis and control equipment (device or device). The fault diagnosis and control equipment (device or device) includes a virtual impedance setting module, an AC current reconstruction module, an AC sensor fault diagnosis module, an impedance voltage generation module, a control unit, and a differential module. The inverter is connected to the power grid or load through an AC filter inductor L, and R... L Let I be the equivalent resistance of inductor L. The inverter control system acquires the AC current I through a current sensor. ac The voltage sampling circuit acquires the AC voltage V. g .

[0042] The inverter AC current sensor fault diagnosis and control method of the present invention mainly includes the following process.

[0043] Step 1, set the virtual impedance Z v Its complex domain expression is:

[0044] Zv =L v s+R v

[0045] Where L v For virtual inductance, R v Let S be the virtual resistance and S be the complex frequency.

[0046] Step 2: Obtain the AC voltage V collected by the voltage sampling circuit. g Simultaneously, the modulation voltage U output by the control unit at the previous moment is acquired. pwm_last The Z v V g U pwm_last Combined with actual impedance Z L The current is reconstructed using an AC current reconstruction algorithm to obtain the reconstructed current I. ac_cal ;

[0047] Actual impedance Z L The complex domain expression is:

[0048] Z L =Ls+R L

[0049] Where L is the AC filter inductance, R L Let L be the equivalent resistance of the inductor, and S be the complex frequency.

[0050] The current is reconstructed using the impedance current-voltage characteristic, and the algorithm is as follows:

[0051]

[0052] Where the virtual impedance Z v Relative to Z v +Z L The larger the proportion, the higher the reconstruction accuracy, which is affected by the actual impedance Z. L The smaller the impact.

[0053] Step 3: Perform AC sensor fault diagnosis and output corresponding control signals; first, acquire the AC current I collected by the current sensor. ac The instantaneous value of the current residual is calculated, and the instantaneous value of the current residual is equal to the reconstructed current I. ac_cal With alternating current I ac The difference is used to obtain the absolute value I of the residual current. ac_dif With effective value I ac_dif_rms Then, using the absolute value I of the obtained residual current... ac_dif With effective value I ac_dif_rms Perform fault logic judgment, and generate AC current control feedback signal S based on the judgment result. conThe system switches to step 4; if a fault shutdown condition is triggered, a fault shutdown control signal S is output. W The process ends when the machine reaches the control unit and stops. Details are as follows:

[0054] If I ac_dif If the upper limit threshold Thb is exceeded, a fault shutdown condition is triggered, and a fault shutdown control signal S is output. W The signal is sent to the control unit, which then controls the shutdown. If the upper limit threshold Thb is not exceeded but the lower limit threshold Tha is exceeded, an AC current control feedback signal S is sent. con The switch, at this time S con =I ac_cal If I ac_dif If the current is less than the lower threshold Tha, the AC current control feedback signal S will not be triggered. con The switch, at this time S con =I ac If the AC current control feedback signal S is triggered con After the switch, if the system runs for more than t1 during the AC current sensor fault period, it will trigger the fault shutdown condition and output the fault shutdown control signal S. W The system is directed to the control unit, which then controls the shutdown. If the running time does not exceed t1, the effective value of the current residual I is calculated. ac_dif_rms Judgment, I ac_dif_rms When the current is less than the upper limit threshold Thb and the duration is greater than t2, the control feedback signal of the AC current is restored to S. con =I ac Among them, t1 and t2 are set according to the actual working conditions, for example, t1 is set to 10 seconds and t2 is set to 5 seconds.

[0055] Step 4: Control the feedback signal S using the generated AC current. con With the set virtual impedance Z v Calculate the impedance voltage U v The calculation formula is:

[0056] Uv=ZvScon

[0057] The above calculation formulas are based on Ohm's law for circuits.

[0058] At the same time, the control unit controls the feedback signal S based on the acquired AC current. con Generate the corresponding control voltage signal U pwm ;

[0059] Step 5, control voltage signal U pwm With impedance voltage U v The difference is calculated by introducing the effect of impedance voltage drop into the control loop to obtain the modulated voltage signal U of the inverter. pwm_refThe PWM generation and driving circuit is based on the U pwm_ref The power switch is generated to drive the PWM signal to control the inverter system.

[0060] Figure 3 This is a schematic diagram of the AC current waveform reconstructed by the AC current sensor when the equivalent inductance and resistance components of the inverter in this invention remain unchanged. When the AC inductor impedance remains constant and matches the impedance in the control software, the reconstructed current I... ac_cal With the actual sampled AC current I ac The absolute value of the residual is less than 0.5A, indicating accurate reconstruction.

[0061] Figure 4 This is a schematic diagram of the AC current waveform reconstructed by the AC current sensor when the equivalent inductance of the inverter in this invention decreases by 50% and the resistance measurement error is 50%. When the actual inductance undergoes nonlinear changes or deviates significantly from the impedance set by the control software, the reconstructed current I... ac_cal With the actual sampled AC current I ac Even with an absolute residual value of <2A, the reconstruction accuracy remains high, and its accuracy can be adjusted as needed by increasing the set virtual impedance Z. v Value to improve;

[0062] Figure 5 This is a schematic diagram showing the reconstructed current and current residual when the AC current sensor of the inverter of the present invention experiences a short-circuit fault. When the AC current sensor experiences a short-circuit fault, the sampled AC current I... ac When it becomes 0, the current residual I ac_dif The rapid increase within 10ms can be used to quickly identify faults in current sensors.

[0063] Figure 6 This is a diagram showing the change in inverter output current and system protection when a short-circuit fault occurs in the AC current sensor of the inverter according to the present invention. When a short-circuit fault occurs in the current sensor, the current residual I... ac_dif If the threshold Tha is exceeded at time t1, the current control feedback switching S is triggered. con =I ac_cal The actual alternating current I ac The impact is relatively small and controlled below the threshold Tha. After a period of time, reaching time t2, the system determines a fault and shuts down because the AC current sensor is still in a fault state. The entire process ensures smooth and controllable current flow, effectively protecting the inverter. (See diagram i) ac The actual AC current waveform, compared with the digitally sampled I... ac The shape is the same, except that the actual AC current waveform has inductive current ripple, which is filtered out after digital sampling.

[0064] Example 2:

[0065] like Figure 7 As shown, this invention also provides an inverter AC current sensor fault diagnosis and control device. The device includes at least one processor and at least one memory, as well as a communication interface and an internal bus. The memory stores a computer-executable program. When the processor executes the executable program stored in the memory, the device executes the inverter AC current sensor fault diagnosis and control method as described in Embodiment 1. The internal bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, the bus in the accompanying drawings is not limited to only one bus or one type of bus. The memory may include high-speed RAM memory, and may also include non-volatile memory (NVM), such as at least one disk storage device, or a USB flash drive, portable hard drive, read-only memory, disk, or optical disk, etc. The device can be provided as a terminal, server, or other form of device.

[0066] Figure 7 This is a block diagram illustrating an illustrative device. The device may include one or more of the following components: a processing component, a memory, a power supply component, a multimedia component, an audio component, an input / output (I / O) interface, a sensor component, and a communication component. The processing component typically controls the overall operation of the electronic device, such as operations associated with display, telephone calls, data communication, camera operation, and recording operations. The processing component may include one or more processors to execute instructions to perform all or part of the steps of the methods described above. Furthermore, the processing component may include one or more modules to facilitate interaction between the processing component and other components. For example, the processing component may include a multimedia module to facilitate interaction between the multimedia component and the processing component.

[0067] Memory is configured to store various types of data to support the operation of electronic devices. Examples of this data include instructions for any application or method used to operate on an electronic device, contact data, phonebook data, messages, pictures, videos, etc. Memory can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0068] A power supply component provides power to various components of an electronic device. The power supply component may include a power management system, one or more power supplies, and other components associated with generating, managing, and distributing power to the electronic device. A multimedia component includes a screen that provides an output interface between the electronic device and the user. In some embodiments, the screen may include a liquid crystal display (LCD) and a touch panel (TP). If the screen includes a touch panel, the screen may be implemented as a touchscreen to receive input signals from the user. The touch panel includes one or more touch sensors to sense touches, swipes, and gestures on the touch panel. The touch sensors may sense not only the boundaries of the touch or swipe action but also the duration and pressure associated with the touch or swipe operation. In some embodiments, the multimedia component includes a front-facing camera and / or a rear-facing camera. When the electronic device is in an operating mode, such as a shooting mode or a video mode, the front-facing camera and / or the rear-facing camera may receive external multimedia data. Each front-facing and rear-facing camera may be a fixed optical lens system or have focal length and optical zoom capabilities.

[0069] The audio component is configured to output and / or input audio signals. For example, the audio component includes a microphone (MIC) configured to receive external audio signals when the electronic device is in an operating mode, such as call mode, recording mode, or voice recognition mode. The received audio signals may be further stored in memory or transmitted via a communication component. In some embodiments, the audio component also includes a speaker for outputting audio signals. The I / O interface provides an interface between the processing component and peripheral interface modules, which may be a keyboard, click wheel, buttons, etc. These buttons may include, but are not limited to, a home button, volume buttons, a power button, and a lock button.

[0070] The sensor assembly includes one or more sensors for providing state assessments of various aspects of the electronic device. For example, the sensor assembly can detect the on / off state of the electronic device, the relative positioning of components such as the display and keypad of the electronic device, changes in the position of the electronic device or a component of the electronic device, the presence or absence of user contact with the electronic device, the orientation or acceleration / deceleration of the electronic device, and temperature changes of the electronic device. The sensor assembly may include a proximity sensor configured to detect the presence of nearby objects without any physical contact. The sensor assembly may also include an optical sensor, such as a CMOS or CCD image sensor, for use in imaging applications. In some embodiments, the sensor assembly may also include an accelerometer, a gyroscope, a magnetometer, a pressure sensor, or a temperature sensor.

[0071] The communication component is configured to facilitate wired or wireless communication between electronic devices and other devices. The electronic device can access wireless networks based on communication standards, such as WiFi, 2G, or 3G, or combinations thereof. In one exemplary embodiment, the communication component receives broadcast signals or broadcast-related information from an external broadcast management system via a broadcast channel. In one exemplary embodiment, the communication component further includes a Near Field Communication (NFC) module to facilitate short-range communication. For example, the NFC module may be implemented based on Radio Frequency Identification (RFID) technology, Infrared Data Association (IrDA) technology, Ultra-Wideband (UWB) technology, Bluetooth (BT) technology, and other technologies.

[0072] In an exemplary embodiment, the electronic device may be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components to perform the methods described above.

[0073] Example 3:

[0074] The present invention also provides a non-volatile computer-readable storage medium storing a program or instructions that, when executed by a processor, cause a computer to perform the inverter AC current sensor fault judgment and control method as described in Embodiment 1.

[0075] Specifically, a system, apparatus, or device may be provided equipped with a readable storage medium on which software program code implementing the functions of any of the embodiments described above is stored, and the computer or processor of the system, apparatus, or device reads and executes the instructions stored in the readable storage medium. In this case, the program code read from the readable medium itself can implement the functions of any of the embodiments described above, therefore, the machine-readable code and the readable storage medium storing the machine-readable code constitute a part of the present invention.

[0076] The aforementioned storage media can be implemented using any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disks or optical disks (such as CD-ROM, CD-R, CD-RW, DVD-20ROM, DVD-RAM, DVD-RW, DVD-RW), magnetic tape, etc. The storage media can be any available medium accessible to general-purpose or special-purpose computers.

[0077] It should be understood that the aforementioned processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. A general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly manifested as execution by a hardware processor, or execution by a combination of hardware and software modules within the processor.

[0078] It should be understood that the storage medium is coupled to the processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside in application-specific integrated circuits (ASICs). Alternatively, the processor and storage medium can exist as discrete components in a terminal or server.

[0079] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0080] Computer program instructions used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing the status information of the computer-readable program instructions to implement various aspects of this disclosure.

[0081] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

[0082] While the specific embodiments of the present invention have been described above, they are not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for fault diagnosis and control of AC current sensor in an inverter, characterized in that, Includes the following steps: S1, Set the virtual impedance Z v ; S2, acquire the AC voltage V collected by the voltage sampling circuit. g Simultaneously, the modulation voltage U output by the control unit at the previous moment is acquired. pwm_last The Z v V g U pwm_last Combined with actual impedance Z L The current is reconstructed using an AC current reconstruction algorithm to obtain the reconstructed current I. ac_cal ; S3 performs AC sensor fault diagnosis and outputs corresponding control signals; first, it acquires the AC current I collected by the current sensor. ac The instantaneous value of the current residual is calculated, and the instantaneous value of the current residual is equal to the reconstructed current I. ac_cal With alternating current I ac The difference is used to obtain the absolute value I of the residual current. ac_dif With effective value I ac_dif_rms Then, using the absolute value I of the obtained residual current... ac_dif With effective value I ac_dif_rms Perform fault logic judgment, and generate AC current control feedback signal S based on the judgment result. con The system switches to S4; if a fault stop condition is triggered, a fault stop control signal S is output. W The system is directed to the control unit, which then controls the shutdown. S4 controls the feedback signal S through the generated alternating current. con With the set virtual impedance Z v Calculate the impedance voltage U v Simultaneously, the control unit obtains the AC current control feedback signal S. con Generate the corresponding control voltage signal U pwm ; S5, the control voltage signal U pwm With impedance voltage U v The difference is calculated by introducing the effect of impedance voltage drop into the control loop to obtain the modulated voltage signal U of the inverter. pwm_ref The PWM generation and driving circuit is based on the U pwm_ref Generate a power switch to drive the PWM signal to control the inverter system; The virtual impedance Z in S1 v The complex domain expression is: Where L v For virtual inductance, R v Here, S is the virtual resistance, and S is the complex frequency. The actual impedance Z in S2 L The complex domain expression is: Where L is the AC filter inductance, R L Let L be the equivalent resistance of the inductor, and S be the complex frequency. The AC current reconstruction algorithm formula in S2 is as follows: Where the virtual impedance Z v Relative to Z v +Z L The larger the proportion, the higher the reconstruction accuracy, which is affected by the actual impedance Z. L The smaller the impact.

2. The method for fault diagnosis and control of inverter AC current sensor as described in claim 1, characterized in that, The specific process of fault logic judgment in S3 is as follows: If I ac_dif If the upper limit threshold Thb is exceeded, a fault shutdown condition is triggered, and a fault shutdown control signal S is output. W The signal is sent to the control unit, which then controls the shutdown. If the upper limit threshold Thb is not exceeded but the lower limit threshold Tha is exceeded, an AC current control feedback signal S is sent. con The switch, at this time S con = I ac_cal If I ac_dif If the current is less than the lower threshold Tha, the AC current control feedback signal S will not be triggered. con The switch, at this time S con =I ac If the AC current control feedback signal S is triggered con After the switch, if the system runs for more than t1 during the AC current sensor fault period, it will trigger the fault shutdown condition and output the fault shutdown control signal S. W The system is directed to the control unit, which then controls the shutdown. If the running time does not exceed t1, then the effective value of the current residual I is calculated. ac_dif_rms Judgment, I ac_dif_rms When the current is less than the upper limit threshold Thb and the duration is greater than t2, the control feedback signal of the AC current is restored to S. con =I ac .

3. The method for fault diagnosis and control of inverter AC current sensor as described in claim 1, characterized in that: The feedback signal S in S4 is controlled by the generated alternating current. con With the set virtual impedance Z v Calculate the impedance voltage U v The calculation formula is: The above calculation formulas are based on Ohm's law for circuits.

4. A fault diagnosis and control device for an inverter AC current sensor, characterized in that: The device includes at least one processor and at least one memory, the processor and the memory being coupled together; the memory stores a computer program; when the processor executes the computer program stored in the memory, the device implements the inverter AC current sensor fault judgment and control method as described in any one of claims 1 to 3.

5. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a program or instructions that, when executed by a processor, cause the computer to perform the inverter AC current sensor fault diagnosis and control method as described in any one of claims 1 to 3.

6. A fault diagnosis and control system for an inverter AC current sensor, characterized in that: The device includes the inverter AC current sensor fault diagnosis and control equipment as described in claim 4, and also includes a current sensor, a voltage sampling circuit and a PWM generation and drive circuit. The inverter is connected to the power grid or load through an AC filter inductor L.

Images