CT reverse connection adaptive inverter control system and method

Abstract

The invention discloses a CT reverse connection adaptive inverter control system and method. According to the scheme provided by the invention, the automatic detection and self-adaptive correction of the reverse connection of the current transformer are realized, the automation degree and reliability of the system are improved, the workload of manual inspection and correction is reduced, and the corresponding labor cost is greatly saved. The current signal is directly corrected, the tedious operation of manual correction is avoided, the overall checking and correcting efficiency is effectively improved, meanwhile, the checking and correcting accuracy can be guaranteed, the situation of misjudgment or omission existing in the manual checking and correcting process is avoided, and the checking and correcting efficiency is improved. The operation stability and safety of an inverter system are effectively ensured, and abnormal conditions caused by reverse connection of the current transformer are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics, and in particular to a CT reverse connection adaptive inverter control system and method. Background Art

[0002] In the inverter control system, the installation direction of the current transformer (CT) plays a vital role in the normal operation of the system. If the CT is connected in reverse, the phase of the collected current signal will be wrong, which will affect the normal control of the inverter. In traditional processes, it is necessary to rely on manual inspection and correction of the installation direction of the CT, which increases labor costs and operational complexity. The troubleshooting process is time-consuming, labor-intensive and inefficient. In addition, manual inspection alone is prone to misjudgment or missed judgment, which poses a safety hazard and affects the safety and reliability of the equipment.

[0003] Therefore, the prior art has defects and needs to be improved. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a CT reverse connection adaptive inverter control system and method.

[0005] The technical solution of the present invention is as follows: a CT reverse connection adaptive inverter control system is provided, comprising: a current transformer, an analog-to-digital converter, a voltage acquisition module, a control module, and a protection device, wherein the current transformer and the voltage acquisition module are electrically connected to the analog-to-digital converter respectively, and the control module is electrically connected to the analog-to-digital converter, the memory and the protection device, wherein:

[0006] Current transformer: used to collect grid current signals;

[0007] Voltage acquisition module: used to collect grid voltage signals;

[0008] Analog-to-digital converter: used to convert analog signals of current and voltage into digital signals;

[0009] Control module: used to process the collected current digital signal and voltage digital signal, execute signal processing and signal analysis algorithms, and continuously and periodically output algorithm processing results to the display device and protection device;

[0010] Protective device: used to quickly disconnect the circuit when an abnormality is detected.

[0011] Furthermore, the control module adopts one of a microcontroller or a digital signal processor.

[0012] Furthermore, the voltage acquisition module uses a voltage sensor to acquire voltage.

[0013] Furthermore, a memory is integrated inside the control module, and the memory is used to store historical data and algorithm parameters.

[0014] Furthermore, the control module is connected to a display device.

[0015] The present invention also provides a CT reverse connection adaptive inverter control method, which uses the CT reverse connection adaptive inverter control system as described above to control the inverter, comprising the following steps:

[0016] Step 1: The current signal in the power grid is collected through the current transformer, the voltage signal in the power grid is collected through the voltage collection module, and the collected current signal and voltage signal are sent to the analog-to-digital converter respectively;

[0017] Step 2: The analog-to-digital converter processes the current signal and the voltage signal, converts the current signal and the voltage signal into digital signals, and sends the converted digital signals to the control module;

[0018] Step 3: In the control module, a phase analysis is performed on the received digital signal to analyze the phase relationship between the current signal and the voltage signal;

[0019] Step 4: Determine whether the current transformer is reversely connected based on the phase analysis results. If reverse connection occurs, correct the polarity of the current signal.

[0020] Step 5: Continuously monitor the phase relationship between the current signal and the voltage signal, periodically calculate the phase difference, and display the correction status in real time on the display device;

[0021] Step 6: When an abnormal change in the magnitude of the current signal is detected, the protection device is controlled through the GPIO interface to cut off the circuit.

[0022] Furthermore, in step 3, the phase relationship between the current signal and the voltage signal is analyzed by using fast Fourier transform or phase-locked loop technology to calculate the phase difference; the specific steps are:

[0023] Step 3.1: Retrieve algorithm data related to phase analysis from the memory integrated in the control module;

[0024] Step 3.2: Perform fast Fourier transform on the collected current signal and voltage signal according to the called algorithm data;

[0025] Step 3.3: Extract the fundamental wave phase according to the signal obtained after the fast Fourier transform, and calculate the phase difference between the current signal and the voltage signal according to the extracted fundamental wave phase.

[0026] Furthermore, the specific steps of step 4 are:

[0027] Step 4.1: Set a conditional statement in the control module. If an abnormal phase difference is detected, the collected current signal is multiplied by -1 for correction;

[0028] Step 4.2: After the calibration is performed, the control module sends a CT reverse connection calibrated signal to the display, and the display device displays that the CT reverse connection has been calibrated.

[0029] By adopting the above scheme, in the scheme provided by the present invention, automatic detection and adaptive correction of reverse connection of current transformer are realized, the automation and reliability of the system are improved, and the workload of manual inspection and correction is reduced, which greatly saves the corresponding labor cost. In addition, the present invention directly corrects the current signal, avoids the cumbersome operation of manual correction, effectively improves the overall inspection and correction efficiency, and at the same time, can ensure the accuracy of inspection and correction, avoid misjudgment or omission in the process of manual inspection and correction, effectively ensure the operation stability and safety of the inverter system, and avoid abnormal conditions caused by reverse connection of current transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the system framework of the present invention.

[0031] Figure 2 Schematic diagram of information acquisition box phase analysis.

[0032] Figure 3 This is the adaptive correction flow chart.

[0033] Figure 4 The figure is a flow chart of the protection mechanism. DETAILED DESCRIPTION

[0034] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0035] See also Figure 1 The present invention provides a CT reverse connection adaptive inverter control system, comprising: a current transformer, an analog-to-digital converter, a voltage acquisition module, a control module, and a protection device, wherein the current transformer and the voltage acquisition module are electrically connected to the analog-to-digital converter respectively, and the control module is electrically connected to the analog-to-digital converter, the memory, and the protection device, wherein:

[0036] Current transformer (CT sensor): used to collect grid current signals.

[0037] Voltage acquisition module: used to collect grid voltage signals.

[0038] Analog-to-digital converter (ADC): used to periodically collect current signals and voltage signals through current transformers and voltage acquisition modules, convert the analog signals of current and voltage into digital signals, and store the generated digital signals in a buffer.

[0039] Control module: used to process the collected current digital signal and voltage digital signal, execute signal processing and signal analysis algorithms, and output the algorithm processing results to the display device and protection device periodically and uninterruptedly. When the analog-to-digital converter sends the current signal and voltage signal to the control module, the phase relationship between the current signal and the voltage signal is analyzed through the fast Fourier transform (FFT) or phase-locked loop (PLL) technology. Using the phase-locked loop (PLL) technology instead of the fast Fourier transform (FFT) for phase analysis can improve real-time performance and computing efficiency. Write FFT or PLL algorithms in the control program to process the collected data in real time and calculate the phase difference between current and voltage. According to the phase analysis results, it is judged whether the current transformer is reversely connected. If it is reversely connected, the collected current signal is multiplied by -1 to perform adaptive correction on the current signal. In the adaptive correction, in addition to the simple current polarity reversal, a phase compensation algorithm can also be added to improve the overall correction accuracy.

[0040] Protection device: used to quickly disconnect the circuit when an abnormality is detected. When the monitored current is too large or too small, the protection device is activated to disconnect the circuit path to protect the safety of the entire circuit. In some embodiments, the circuit breaker or protection relay used as the protection device is generally controlled through the GPIO interface to avoid damage to circuit components due to excessive current.

[0041] In some embodiments, the control module is implemented as a microcontroller or a digital signal processor (DSP).

[0042] A microcontroller is an integrated circuit chip that integrates a CPU, memory, input and output ports, and various system control logic circuits. Microcontrollers are programmable, scalable, simple in structure, and low in power consumption. They are widely used in electronic computers, communication equipment, home appliances, automotive control, medical equipment, and aerospace.

[0043] A digital signal processor is a microprocessor designed specifically for digital signal processing. It can process digital signals quickly and efficiently. DSP processors usually have high-speed computing capabilities, powerful instruction sets, and flexible programming methods, making them suitable for real-time signal processing tasks.

[0044] The voltage acquisition module uses a voltage sensor to collect voltage. A voltage sensor is a device that detects voltage and converts it into a usable electrical signal output. Its main function is to convert high voltage, low voltage or dangerous voltage into a low voltage signal for easy measurement, monitoring and control. The voltage sensor can provide accurate voltage measurement, and the error range is usually very small.

[0045] In some embodiments, the control module is internally integrated with a memory, which is used to store historical data and algorithm parameters. By setting up the memory, the digital signals corresponding to the current signal and the voltage signal generated after the analog-to-digital converter conversion can be cached, and the algorithm-related data required for the control module to perform phase analysis on the digital signals corresponding to the current signal and the voltage signal can be stored, so that the control module can quickly call it.

[0046] The control module is connected to a display device to display the various working parameters of the control module in real time, display the collected current signal and voltage signal in numerical form, and display corresponding alarm prompts when there are abnormalities in the current or voltage values, so that the operator can quickly identify the working status of the overall system and quickly respond to and handle abnormal conditions.

[0047] The present invention also provides a CT reverse connection adaptive inverter control method, which uses the CT reverse connection adaptive inverter control system as described above to control the inverter, comprising the following steps:

[0048] Step 1: The current signal in the power grid is collected through the current transformer, the voltage signal in the power grid is collected through the voltage collection module, and the collected current signal and voltage signal are sent to the analog-to-digital converter respectively.

[0049] Step 2: The analog-to-digital converter processes the current signal and the voltage signal, converts the current signal and the voltage signal into digital signals, and sends the converted digital signals to the control module.

[0050] Before starting work, write the corresponding software code. The analog-to-digital converter periodically collects the current and voltage signals in the power grid through the current transformer and the voltage acquisition module. Set the interrupt service routine (ISR) in the control program to read the current and voltage data collected by the mode converter at a fixed frequency and store them in the buffer. Among them, the instruction code at the software level is:

[0051]

[0052]

[0053] Step 3: Please refer to Figure 2In the control module, the received digital signal is subjected to phase analysis to analyze the phase relationship between the current signal and the voltage signal. By adopting the fast Fourier transform or phase-locked loop technology, the phase relationship between the current signal and the voltage signal is analyzed to calculate the phase difference. The specific steps are as follows:

[0054] Step 3.1: Retrieve algorithm data related to phase analysis from the memory integrated in the control module;

[0055] Step 3.2: Perform fast Fourier transform on the collected current signal and voltage signal according to the called algorithm data;

[0056] Step 3.3: Extract the fundamental wave phase according to the signal obtained after the fast Fourier transform, and calculate the phase difference between the current signal and the voltage signal according to the extracted fundamental wave phase.

[0057] The instruction code at the software level is:

[0058]

[0059]

[0060] Step 4: Please refer to Figure 3 , determine whether the current transformer is reversely connected based on the phase analysis results. If reverse connection occurs, correct the polarity of the current signal. The specific steps are:

[0061] Step 4.1: Set a conditional statement in the control module. If an abnormal phase difference is detected, the collected current signal is multiplied by -1 for correction;

[0062] Step 4.2: After the calibration is performed, the control module sends a CT reverse connection calibrated signal to the display, and the display device displays that the CT reverse connection has been calibrated.

[0063] The instruction code at the software level is:

[0064]

[0065] Step 5: Continuously monitor the phase relationship between the current signal and the voltage signal, periodically calculate the phase difference, and display the correction status in real time on the display device.

[0066] The instruction code at the software level is:

[0067]

[0068]

[0069] Step 6: See Figure 4When an abnormal change in the magnitude of the current signal is detected, the protection device is controlled through the GPIO interface to cut off the circuit. In some embodiments, a circuit breaker or a protection relay is used as the protection device, and the control module starts the circuit breaker or the protection relay through the GPIO interface, so that the circuit connection can be disconnected in time when an abnormal condition occurs, ensuring the safety of the overall system.

[0070] The instruction code at the software level is:

[0071]

[0072]

[0073] In the solution provided by the present invention, automatic detection and adaptive correction of reverse connection of current transformer are realized, the automation and reliability of the system are improved, and the workload of manual inspection and correction is reduced, which greatly saves the corresponding labor costs. In addition, the present invention directly corrects the current signal, avoids the cumbersome operation of manual correction, effectively improves the overall inspection and correction efficiency, and at the same time, can ensure the accuracy of inspection and correction, avoid misjudgment or omission in the process of manual inspection and correction, effectively ensure the operation stability and safety of the inverter system, and avoid abnormal situations caused by reverse connection of current transformer.

[0074] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A CT reverse connection adaptive inverter control system, characterized in that: include: A current transformer, an analog-to-digital converter, a voltage acquisition module, a control module, and a protection device, wherein the current transformer and the voltage acquisition module are electrically connected to the analog-to-digital converter respectively, and the control module is electrically connected to the analog-to-digital converter, the memory, and the protection device, wherein: Current transformer: used to collect grid current signals; Voltage acquisition module: used to collect grid voltage signals; Analog-to-digital converter: used to convert analog signals of current and voltage into digital signals; Control module: used to process the collected current digital signal and voltage digital signal, execute signal processing and signal analysis algorithms, and continuously and periodically output algorithm processing results to the display device and protection device; Protective device: used to quickly disconnect the circuit when an abnormality is detected.

2. The CT reverse connection adaptive inverter control system according to claim 1, characterized in that: The control module adopts one of a microcontroller and a digital signal processor.

3. The CT reverse connection adaptive inverter control system according to claim 1, characterized in that: The voltage acquisition module uses a voltage sensor to acquire voltage.

4. The CT reverse connection adaptive inverter control system according to claim 1, characterized in that: The control module is internally integrated with a memory, and the memory is used to store historical data and algorithm parameters.

5. The CT reverse connection adaptive inverter control system according to claim 1, characterized in that: The control module is connected with a display device.

6. A CT reverse connection adaptive inverter control method, using the CT reverse connection adaptive inverter control system according to any one of claims 1 to 4 to control the inverter, characterized in that: The steps include: Step 1: The current signal in the power grid is collected through the current transformer, the voltage signal in the power grid is collected through the voltage collection module, and the collected current signal and voltage signal are sent to the analog-to-digital converter respectively; Step 2: The analog-to-digital converter processes the current signal and the voltage signal, converts the current signal and the voltage signal into digital signals, and sends the converted digital signals to the control module; Step 3: In the control module, a phase analysis is performed on the received digital signal to analyze the phase relationship between the current signal and the voltage signal; Step 4: Determine whether the current transformer is reversely connected based on the phase analysis results. If reverse connection occurs, correct the polarity of the current signal. Step 5: Continuously monitor the phase relationship between the current signal and the voltage signal, periodically calculate the phase difference, and display the correction status in real time on the display device; Step 6: When an abnormal change in the magnitude of the current signal is detected, the protection device is controlled through the GPIO interface to cut off the circuit.

7. The CT reverse connection adaptive inverter control method according to claim 6, characterized in that: In step 3, the phase relationship between the current signal and the voltage signal is analyzed by using fast Fourier transform or phase-locked loop technology to calculate the phase difference; the specific steps are: Step 3.1: Retrieve algorithm data related to phase analysis from the memory integrated in the control module; Step 3.2: Perform fast Fourier transform on the collected current signal and voltage signal according to the called algorithm data; Step 3.3: Extract the fundamental wave phase according to the signal obtained after the fast Fourier transform, and calculate the phase difference between the current signal and the voltage signal according to the extracted fundamental wave phase.

8. The CT reverse connection adaptive inverter control method according to claim 6, characterized in that: The specific steps of step 4 are: Step 4.1: Set a conditional statement in the control module. If an abnormal phase difference is detected, the collected current signal is multiplied by -1 for correction; Step 4.2: After the calibration is performed, the control module sends a CT reverse connection calibrated signal to the display, and the display device displays that the CT reverse connection has been calibrated.

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