Voltage and current combined transformer and control method

Abstract

The invention relates to the technical field of power electronics, particularly provides a voltage and current combined transformer and a control method, and aims to solve the technical problems that in the prior art, a voltage and current transformer is poor in stability, the accuracy is difficult to guarantee, and the safety is poor. Therefore, the voltage and current combined type mutual inductor comprises a first function module, a second function module and an optical fiber transmission line, the first function module is used for generating acquisition signals and sending the acquisition signals and power supply electric energy to the second function module through the optical fiber transmission line, and the second function module is used for generating power supply electric energy; and receiving the voltage or current signal of the circuit to be tested transmitted by the second function module through the optical fiber transmission line, and converting the voltage or current signal so as to be read by external equipment. And the second function module is used for receiving the acquisition signal and the power supply electric energy from the first function module, acquiring a voltage or current signal of the to-be-tested circuit based on the acquisition signal, and transmitting the acquired voltage or current signal of the to-be-tested circuit to the first function module through the optical fiber transmission line.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a voltage-current combined transformer and a control method thereof. Background Art

[0002] Traditional electrical measurement methods mostly use electromagnetic voltage transformers and electromagnetic current transformers, which work based on the principle of electromagnetic coupling. Specifically, the voltage transformer converts the high voltage on the primary side into the low voltage on the secondary side, and the current transformer converts the large current on the primary side into the small current on the secondary side for easy measurement. However, this type of transformer has some significant problems:

[0003] Electromagnetic voltage transformer: Excitation current will cause measurement errors; when short-circuited, the thermal effect and electromotive force of the huge current will increase the signal conversion error; at the same time, its nonlinear characteristics can easily lead to waveform distortion.

[0004] Electromagnetic current transformer: When the secondary circuit is open or in poor contact, it may cause secondary overvoltage, which may burn the secondary terminals and even cause power outages or fires. In addition, there is a hidden danger of "power loss". Once a power supply failure occurs, the high-voltage measuring end will not be able to operate normally.

[0005] In summary, although traditional electromagnetic mutual inductors are widely used, their measurement accuracy and safety have certain limitations, especially in high-voltage environments. In addition, high-voltage scenarios have extremely high requirements for insulating materials and are difficult to manufacture, which further increases manufacturing costs.

[0006] Accordingly, the art needs a new voltage and current transformer solution to solve the above problems. Summary of the invention

[0007] In order to overcome the above-mentioned defects, the present application is proposed to solve or at least partially solve the technical problems in the prior art that voltage and current transformers have poor stability, are susceptible to various complex interferences, are difficult to ensure measurement accuracy, and have safety shortcomings.

[0008] In a first aspect, a voltage-current combined transformer is provided, comprising: a first functional module, a second functional module, and an optical fiber transmission line, wherein the first functional module is used to generate a collection signal, and send the collection signal and power supply energy to the second functional module through the optical fiber transmission line, and receive the voltage or current signal of the circuit to be tested transmitted by the second functional module through the optical fiber transmission line, and convert it for reading by an external device; the second functional module is used to receive the collection signal and power supply energy from the first functional module, obtain the voltage or current signal of the circuit to be tested based on the collection signal, and transmit the collected voltage or current signal of the circuit to be tested to the first functional module through the optical fiber transmission line.

[0009] In a technical solution of the above-mentioned voltage-current combined transformer, the optical fiber transmission line includes a first transmission line and a second transmission line; the first functional module includes a control module, a laser emission module, a collection signal receiving module, a power input port, a ground port and a signal output port; the control module is used to generate a collection signal, and send the collection signal and the power supply energy from the power input port to the laser emission module, and obtain the voltage or current signal of the circuit to be tested sent by the collection signal receiving module, and convert the voltage or current signal and output it through the signal output port.

[0010] In a technical solution of the above-mentioned voltage-current combined transformer, the laser emission module is used to receive the collection signal and power supply energy from the control module, convert the collection signal and power supply energy into corresponding optical signals and optical energy respectively, and transmit the optical signal and optical energy to the second functional module through a second transmission line.

[0011] In a technical solution of the above-mentioned voltage-current combined transformer, the second functional module includes a photoelectric conversion module, a signal processing module and a collection module; the photoelectric conversion module is used to obtain the optical signal and light energy, and convert the optical signal and light energy into a collection signal and power supply energy respectively, send the collection signal to the signal processing module, and use the power supply energy to power the signal processing module.

[0012] In a technical solution of the above-mentioned voltage-current combined transformer, the signal processing module includes a clock module, a chip selection module, a data synchronization module, an analog-to-digital conversion module, and a sampling and amplification module; the clock module is used to obtain the acquisition signal, convert the acquisition signal into a clock signal, and send the clock signal to the chip selection module, the data synchronization module and the analog-to-digital conversion module respectively; and / or, the chip selection module is used to obtain the clock signal, convert the clock signal into a chip selection signal, and send the chip selection signal to the analog-to-digital conversion module.

[0013] In a technical solution of the above-mentioned voltage-current combined transformer, the sampling and amplification module is used to obtain the analog signal of the circuit to be tested collected by the acquisition module, amplify the analog signal, and send the amplified analog signal to the analog-to-digital conversion module; and / or, the analog-to-digital conversion module is used to obtain the clock signal, the chip select signal and the amplified analog signal, convert the amplified analog signal into a digital signal based on the clock signal and the chip select signal, and send the digital signal to the data synchronization module; and / or, the data synchronization module is used to obtain the clock signal, convert the digital signal into an optical signal based on the clock signal, and send the optical signal to the acquisition signal receiving module through the first transmission line.

[0014] In a technical solution of the above-mentioned voltage-current combined transformer, the acquisition module includes a voltage acquisition module; the voltage acquisition module includes a first voltage divider element, a second voltage divider element and a third voltage divider element connected in series; the voltage acquisition module is used to use the first voltage divider element, the second voltage divider element and the third voltage divider element to divide the circuit to be tested when the acquisition signal is the acquisition voltage, so that the sampling and amplification module acquires the analog signal at both ends of the second voltage divider element after the voltage division.

[0015] In a technical solution of the above-mentioned voltage-current combined transformer, the acquisition module includes a current acquisition module; the current acquisition module is used to acquire the analog signal of the circuit to be tested and send it to the sampling and amplification module when the acquisition signal is the acquisition current.

[0016] In a technical solution of the above-mentioned voltage-current combined transformer, the acquisition signal receiving module is used to receive the optical signal sent by the data synchronization module, convert the optical signal into a voltage or current signal of the circuit to be tested, and send the voltage or current signal of the circuit to be tested to the control module.

[0017] In a second aspect, a control method for a voltage-current combined transformer is provided, and the method is performed based on the voltage-current combined transformer described in any one of the technical solutions of the above-mentioned voltage-current combined transformer, and the method includes: a first functional module generates an acquisition signal, and sends the acquisition signal and power supply energy to a second functional module through an optical fiber transmission line; the second functional module acquires a voltage or current signal of a circuit to be tested based on the acquisition signal, and sends the voltage or current signal to the first functional module through the optical fiber transmission line; the first functional module obtains the voltage or current signal through the optical fiber transmission line, converts the voltage or current signal, and outputs the converted signal.

[0018] The above one or more technical solutions of the present application have at least one or more of the following beneficial effects:

[0019] The voltage and current combined transformer provided in the present application includes: a first functional module, a second functional module, and an optical fiber transmission line, wherein the first functional module is used to generate a collection signal, and send the collection signal and power supply energy to the second functional module through the optical fiber transmission line, and receive the voltage or current signal of the circuit to be tested transmitted by the second functional module through the optical fiber transmission line, and convert it for reading by an external device; the second functional module is used to receive the collection signal and power supply energy from the first functional module, obtain the voltage or current signal of the circuit to be tested based on the collection signal, and transmit the collected voltage or current signal of the circuit to be tested to the first functional module through the optical fiber transmission line. The present application uses an optical fiber transmission line to transmit power supply energy, which avoids the hidden danger of "power failure" when using high-voltage equipment or the line's own power supply, improves system stability, and effectively isolates the first functional module from the second functional module through the optical fiber transmission line, which can improve safety and is more suitable for high-voltage applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The disclosure of the present application will become easier to understand with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present application. Among them:

[0021] Figure 1 is a schematic diagram of the main structure of a voltage and current combined transformer according to an embodiment of the present application;

[0022] Figure 2 is a main structural diagram of a signal processing module according to an embodiment of the present application;

[0023] Figure 3 is a schematic diagram of the circuit structure of a chip selection module according to an embodiment of the present application;

[0024] Figure 4 is a main structural diagram of a voltage acquisition module according to an embodiment of the present application;

[0025] Figure 5 is a main structural schematic diagram of a current acquisition module according to an embodiment of the present application;

[0026] Figure 6 It is a schematic flow chart of main steps of a control method of a voltage and current combined transformer according to an embodiment of the present application;

[0027] Reference numerals:

[0028] 10: first functional module; 20: second functional module; 11: control module; 12: laser emission module; 13: acquisition signal receiving module; 21: photoelectric conversion module; 22: acquisition module; 23: signal processing module; 230: clock module; 231: chip selection module; 232: analog-to-digital conversion module; 233: sampling and amplification module; 234: data synchronization module. DETAILED DESCRIPTION

[0029] Some embodiments of the present application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application and are not intended to limit the protection scope of the present application.

[0030] In the description of the present application, "module" and "processor" may include hardware, software or a combination of the two. A module may include hardware circuits, various suitable sensors, communication ports, memory, and may also include software parts, such as program code, or a combination of software and hardware. The processor may be a central processing unit, a microprocessor, an image processor, a digital signal processor or any other suitable processor. The processor has data and / or signal processing functions. The processor may be implemented in software, hardware or a combination of the two. Computer-readable storage media include any suitable medium that can store program code, such as a disk, a hard disk, an optical disk, a flash memory, a read-only memory, a random access memory, etc. The term "A and / or B" means all possible combinations of A and B, such as only A, only B or A and B. The term "at least one A or B" or "at least one of A and B" has a similar meaning to "A and / or B" and may include only A, only B or A and B. The singular terms "one" and "the" may also include plural forms.

[0031] Existing electromagnetic voltage transformers and electromagnetic current transformers have certain defects in the electromagnetic induction process. For example, the excitation current in electromagnetic induction will cause measurement errors of electromagnetic voltage transformers. In addition, electromagnetic voltage transformers will also be affected by the huge current thermal effect and electromotive force caused by short circuits, further increasing the error of signal conversion. In addition, the nonlinear characteristics of the transformer will also affect the measurement accuracy. Electromagnetic current transformers often have secondary open circuit failures. Once the secondary circuit is open or the contact is poor, it will cause secondary overvoltage, which will burn the secondary terminals, causing serious consequences such as power outages and fires.

[0032] To this end, the voltage and current combined transformer provided in the present application includes: a first functional module, a second functional module, and an optical fiber transmission line, wherein the first functional module is used to generate a collection signal, and send the collection signal and power supply energy to the second functional module through the optical fiber transmission line, and receive the voltage or current signal of the circuit to be tested transmitted by the second functional module through the optical fiber transmission line, and convert it for reading by an external device; the second functional module is used to receive the collection signal and power supply energy from the first functional module, obtain the voltage or current signal of the circuit to be tested based on the collection signal, and transmit the collected voltage or current signal of the circuit to be tested to the first functional module through the optical fiber transmission line. The present application uses an optical fiber transmission line to transmit power supply energy, avoids the hidden danger of "power failure" when using high-voltage equipment or the line's own power supply, improves system stability, and effectively isolates the first functional module from the second functional module through the optical fiber transmission line, which can improve safety and be more suitable for high-voltage applications.

[0033] See attached Figure 1 , Figure 1 1 is a schematic diagram of the main structure of a voltage and current combined transformer according to an embodiment of the present application. Figure 1 As shown, the voltage-current combined transformer in this embodiment can be used in high-voltage motor detection occasions, and the voltage-current combined transformer includes: a first functional module, a second functional module, and an optical fiber transmission line, wherein the first functional module is used to generate a collection signal, and send the collection signal and power supply energy to the second functional module through the optical fiber transmission line, and receive the voltage or current signal of the circuit to be tested transmitted by the second functional module through the optical fiber transmission line, and convert it for reading by an external device; the second functional module is used to receive the collection signal and power supply energy from the first functional module, obtain the voltage or current signal of the circuit to be tested based on the collection signal, and transmit the collected voltage or current signal of the circuit to be tested to the first functional module through the optical fiber transmission line.

[0034] Specifically, the voltage-current combined transformer includes a first functional module, a second functional module and an optical fiber transmission line. The first functional module refers to the low-voltage side, and the second functional module refers to the high-voltage side. The first functional module is powered by an external power supply circuit. Data and energy are transmitted between the first functional module and the second functional module through the optical fiber transmission line. The second functional module is connected to the circuit to be tested. The first functional module sends the power supply energy and the acquisition signal to the second functional module through the optical fiber transmission line. The second functional module acquires the voltage or current signal of the circuit to be tested based on the acquisition signal, and sends the acquired voltage or current signal to the first functional module through the optical fiber transmission line.

[0035] This application uses an optical fiber transmission line to connect the first functional module and the second functional module, which can completely isolate the high-voltage side from the low-voltage side, and improve the safety of the voltage and current combined transformer in high-voltage scenarios. In addition, the use of optical fiber power supply instead of traditional power supply methods successfully solves the "power failure" problem, improves the system stability and practical value, and is suitable for large-scale mass production.

[0036] In one embodiment, the optical fiber transmission line includes a first transmission line and a second transmission line; the first functional module includes a control module, a laser emission module, a collection signal receiving module, a power input port, a ground port and a signal output port; the control module is used to generate a collection signal, and send the collection signal and the power supply energy from the power input port to the laser emission module, and obtain the voltage or current signal of the circuit to be tested sent by the collection signal receiving module, and convert the voltage or current signal and output it through the signal output port.

[0037] Specifically, the control module is used to generate an acquisition signal and send the acquisition signal and power supply energy to the laser emission module. The power supply energy refers to the electric energy from the power supply to drive the laser emission module to send the acquisition signal and power supply energy to the second functional module through the first transmission line.

[0038] The control module is also used to receive the voltage or current signal of the circuit to be tested sent by the acquisition signal receiving module. The voltage or current signal of the circuit to be tested sent by the acquisition signal receiving module is a digital signal. The control module demodulates the digital signal and converts the digital signal into a signal in a universal protocol format, such as SPI protocol, I2C protocol, UART protocol, etc., and sends the signal in the universal protocol format to the signal output port so that the external device can read and process it.

[0039] The control module may adopt an FPGA chip, a microcontroller unit MCU, or a logic circuit with similar functions.

[0040] In one embodiment, the laser emission module is used to receive the collection signal and power supply energy from the control module, convert the collection signal and power supply energy into corresponding optical signals and optical energy, respectively, and transmit the optical signals and optical energy to the second functional module through a second transmission line.

[0041] Specifically, the laser emission module is configured to convert the collection signal and power supply energy from the control module into optical signals and optical energy respectively, and then send the optical signals and optical energy to the optoelectronic conversion module of the second functional module through the second transmission line, so as to provide power support and clock source for the operation of the equipment on the high-voltage side.

[0042] An optical fiber transmission line is used to transmit energy and signals between the first functional module located on the low-voltage side and the second functional module located on the high-voltage side, thereby achieving complete isolation and intrinsic safety between high voltage and low voltage, and effectively improving the safety of the system.

[0043] In one embodiment, the second functional module includes a photoelectric conversion module, a signal processing module and a collection module; the photoelectric conversion module is used to obtain the optical signal and light energy, and convert the optical signal and light energy into a collection signal and power supply energy respectively, send the collection signal to the signal processing module, and use the power supply energy to power the signal processing module.

[0044] Specifically, the second functional module includes a photoelectric conversion module, a signal processing module and an acquisition module, wherein the photoelectric conversion module is connected to the first functional module through a second transmission line, receives optical signals and optical energy from the first functional module, and then converts the optical signals and optical energy into acquisition signals and power supply energy respectively, and sends the acquisition signals to the signal processing module, and uses the power supply energy to power each module on the high-voltage side.

[0045] In one embodiment, the signal processing module includes a clock module, a chip select module, a data synchronization module, an analog-to-digital conversion module, and a sampling and amplification module; the clock module is used to obtain the acquisition signal, convert the acquisition signal into a clock signal, and send the clock signal to the chip select module, the data synchronization module and the analog-to-digital conversion module respectively; and / or, the chip select module is used to obtain the clock signal, convert the clock signal into a chip select signal, and send the chip select signal to the analog-to-digital conversion module.

[0046] Specifically, if Figure 2 As shown, the signal processing module includes a clock module, a chip selection module, a data synchronization module, an analog-to-digital conversion module, and a sampling and amplification module.

[0047] The input end of the clock module is connected to the output end of the photoelectric conversion module, and the output end of the clock module is connected to the input end of the chip selection module, the analog-to-digital conversion module, and the data synchronization module respectively. The clock module is used to receive the acquisition signal from the photoelectric conversion module, and convert the acquisition signal into a clock signal with a specific frequency, and then send the clock signal to the chip selection module, the analog-to-digital conversion module, and the data synchronization module respectively. The clock signal is a signal used to control the sampling rate or conversion process of the analog-to-digital conversion module. The clock signal determines the number of samples that the analog-to-digital conversion module can collect per second, that is, the sampling rate.

[0048] Specifically, the output of the chip select module is connected to the input of the analog-to-digital conversion module. The chip select module converts the clock signal from the clock module into a chip select signal, and then sends the chip select signal to the analog-to-digital conversion module. The chip select signal (ChipSelect, CS) is a control signal used to select a specific integrated circuit (IC) or memory chip in a digital electronic system. When the chip select signal of a device is activated, it can be low level valid or high level valid, which means that the device is selected and data transmission can begin. The circuit structure of the chip select module is as follows Figure 3 shown.

[0049] In one embodiment, the sampling and amplification module is used to obtain the analog signal of the circuit to be tested collected by the acquisition module, amplify the analog signal, and send the amplified analog signal to the analog-to-digital conversion module; and / or, the analog-to-digital conversion module is used to obtain the clock signal, the chip select signal and the amplified analog signal, convert the amplified analog signal into a digital signal based on the clock signal and the chip select signal, and send the digital signal to the data synchronization module; and / or, the data synchronization module is used to obtain the clock signal, convert the digital signal into an optical signal based on the clock signal, and send the optical signal to the acquisition signal receiving module through the first transmission line.

[0050] Specifically, the input end of the sampling and amplification module is connected to the output end of the acquisition module, and the output end of the sampling and amplification module is connected to the input end of the analog-to-digital conversion module. The sampling and amplification module is used to obtain the analog signal of the circuit to be tested collected by the acquisition module, amplify the analog signal, and then send the amplified analog signal to the analog-to-digital conversion module.

[0051] The output end of the analog-to-digital conversion module is connected to the input end of the data synchronization circuit. The analog-to-digital conversion module receives the clock signal from the clock module and the chip select signal from the chip select module. The clock signal and the chip select signal constitute the acquisition timing waveform of the analog-to-digital conversion module. The acquisition timing waveform is used to control the sampling and conversion timing of the analog-to-digital conversion module. The analog-to-digital conversion module converts the received amplified analog signal into a digital signal based on the acquisition timing waveform, and then sends the converted digital signal to the data synchronization module.

[0052] The output end of the data synchronization module is connected to the input end of the first functional module through the first transmission line. The data synchronization module is used to receive the clock signal from the clock module and the digital signal from the analog-to-digital conversion module, and under the action of the clock signal, transmit the digital signal from the analog-to-digital conversion module back to the acquisition signal receiving module of the first functional module through the first transmission line.

[0053] In some embodiments, the clock module, chip selection module, and data synchronization module can use low-power FPGA chips. The sampling and amplification module and the analog-to-digital conversion module can use low-power operational amplifiers and analog-to-digital converters (ADCs) to reduce energy consumption. At the same time, by using resistors, capacitors, and comparators to build a chip selection module, the signal selection and transmission path are optimized. In terms of data transmission, pulse signals are used instead of square waves to transmit data, which greatly reduces the overall power consumption and provides support for the efficient and stable operation of the voltage and current combined transformer.

[0054] In one embodiment, the acquisition module includes a voltage acquisition module; the voltage acquisition module includes a first voltage divider element, a second voltage divider element and a third voltage divider element connected in series; the voltage acquisition module is used to use the first voltage divider element, the second voltage divider element and the third voltage divider element to divide the circuit to be tested when the acquisition signal is the acquisition voltage, so that the sampling and amplification module acquires the analog signal at both ends of the second voltage divider element after the voltage division.

[0055] The structure of the voltage acquisition module is as follows: Figure 4 shown.

[0056] Specifically, the first voltage divider element, the second voltage divider element and the third voltage divider element are connected in series; one end of the first voltage divider element is connected to the A phase of the circuit to be tested, the other end of the first voltage divider element is connected to one end of the second voltage divider element, the other end of the second voltage divider element is connected to one end of the third voltage divider element, and the other end of the third voltage divider element is connected to the B phase of the circuit to be tested. The two ends of the second voltage divider element are also respectively connected to the sampling and amplification module, so that the sampling and amplification module collects the voltage at the two ends of the second voltage divider element, and the collected voltage is an analog signal.

[0057] The first voltage divider element, the second voltage divider element and the third voltage divider element may be resistors or capacitors. When the first voltage divider element, the second voltage divider element and the third voltage divider element are all resistors, the first voltage divider element, the second voltage divider element and the third voltage divider element are all high-voltage resistors, the first voltage divider element and the third voltage divider element have larger resistance values, the second voltage divider element has smaller resistance values, and the second voltage divider element has lower resistance values ​​than the first voltage divider element and the third voltage divider element.

[0058] In some embodiments, after the sampling and amplification module collects the voltage across the second voltage divider element, the voltage between phases A and B is calculated using a formula. The calculation formula is: Uab=Vo*(R1+R2+R3) / R2 / A

[0059] Among them, Uab is the voltage between phase A and phase B, Vo is the collected voltage after circuit conversion, A is the amplification factor of the entire circuit, R1 is the resistance value of the first voltage divider element, R2 is the resistance value of the second voltage divider element, and R3 is the resistance value of the third voltage divider element.

[0060] In one embodiment, the acquisition module includes a current acquisition module; the current acquisition module is used to acquire the analog signal of the circuit to be tested and send it to the sampling and amplification module when the acquisition signal is the acquisition current.

[0061] Specifically, the current acquisition module can be a Rogowski coil or a Hall sensor. When the current acquisition module is a Rogowski coil, the structure of the current acquisition module is as follows: Figure 5 As shown. The input end of the sampling and amplification module is connected to the circuit to be tested through the Rogowski coil to collect and amplify the voltage signal induced on the Rogowski coil. When the current of the circuit to be tested flows through the Rogowski coil, the Rogowski coil will sense a voltage signal, which is an analog signal. The sampling and amplification module collects the weak voltage signal induced on the Rogowski coil, amplifies the voltage signal and outputs it to the analog-to-digital conversion module.

[0062] The use of Rogowski coils to collect the current of the circuit to be tested can avoid direct contact with the conductor to be tested, avoiding safety hazards caused by electrical connections, and is safer and more reliable; traditional electromagnetic transformers may generate overvoltage when the secondary circuit is open, thereby damaging the equipment or even causing accidents, but Rogowski coils do not have this problem. Even if the secondary circuit is open, it will not cause any impact on the equipment or system. In addition, Rogowski coils will not have magnetic saturation, have high accuracy, and are not easily interfered with.

[0063] In some embodiments, the current of the circuit to be tested can be inferred from the output signal. The calculation formula is: I=Vo / A0 / A1

[0064] Among them, I is the current of the circuit to be tested, Vo is the output signal, A0 is the current conversion multiple of the Rogowski coil, and A1 is the amplification multiple of the sampling and amplification module.

[0065] In one embodiment, the acquisition signal receiving module is used to receive the optical signal sent by the data synchronization module, convert the optical signal into a voltage or current signal of the circuit under test, and send the voltage or current signal of the circuit under test to the control module.

[0066] Specifically, the input end of the acquisition signal receiving module is connected to the output end of the signal processing module through the first transmission line; the acquisition signal receiving module is used to receive the optical signal from the signal processing module through the first transmission line, convert the optical signal into a digital signal, which is a voltage or current signal of the circuit to be tested, and send the voltage or current signal of the circuit to be tested to the control module.

[0067] In some embodiments, the power supply input port is connected to the power supply circuit, and the power supply input port is used to input power supply energy. Further, the first functional module also includes a grounding protection terminal, and the voltage and current combined transformer is grounded through the grounding protection terminal.

[0068] After actual testing and verification, the voltage and current combined transformer of this application has an accuracy of 0.1 level and above. In terms of hardware design, high-precision, low-temperature drift precision wirewound resistors are selected. At the same time, a 16-bit or higher resolution analog-to-digital converter (ADC) is used to capture subtle voltage and current changes, and the fast conversion speed reduces the error caused by dynamic changes in the signal during the signal conversion process.

[0069] At the software algorithm level, the calibration and compensation algorithm is implemented with the help of field programmable gate array (FPGA) to further improve the accuracy. The specific process is to first perform an initial calibration on the voltage and current combined transformer, measure and record the deviation between the measured value and the actual value under the known standard voltage. In the subsequent actual measurement process, the measurement results are calibrated in real time based on these recorded deviations to correct the measurement error. In addition, a finite impulse response (FIR) filter is used, which can well maintain the phase relationship of the signal while filtering out various interference signals, thereby improving the measurement accuracy. The relevant measured data are detailed in Table 1. Table 1

[0070] See attached Figure 6 , Figure 6The main steps of the control method of the voltage and current combined transformer according to an embodiment of the present application are shown in the flowchart. A control method of a voltage and current combined transformer in this embodiment is performed based on the voltage and current combined transformer described in any embodiment of the above voltage and current combined transformer, and the method includes the following steps:

[0071] Step S101: The first functional module generates a collection signal, and sends the collection signal and power supply energy to the second functional module via an optical fiber transmission line.

[0072] Specifically, the optical fiber transmission line includes a first transmission line and a second transmission line. The first functional module generates a collection signal, and the collection signal includes a collection voltage or a collection current. The collection signal and the power supply energy are converted into an optical signal and optical energy and then sent to the second functional module through the second transmission line.

[0073] Step S102: the second functional module collects the voltage or current signal of the circuit to be tested based on the collected signal, and sends the voltage or current signal to the first functional module through the optical fiber transmission line.

[0074] Specifically, the second functional module converts the optical signal into a collection signal, collects the voltage or current signal of the circuit to be tested based on the collection signal, and processes the collected voltage or current signal. The signal processing process is the same as the processing process of the embodiment of the aforementioned voltage and current combined transformer, which will not be repeated here. The processed signal is then converted into an optical signal and sent back to the first functional module through the first transmission line.

[0075] Step S103: the first functional module obtains the voltage or current signal through the optical fiber transmission line, converts the voltage or current signal, and outputs the converted signal.

[0076] Specifically, after receiving the optical signal from the second functional module, the first functional module converts the optical signal into a digital signal, then demodulates the digital signal to obtain a signal in a universal protocol format, and sends the signal in the universal protocol format to the signal output port for external equipment to read and process.

[0077] It should be pointed out that although the various steps in the above embodiments are described in a specific order, those skilled in the art can understand that in order to achieve the effect of the present application, different steps do not have to be executed in such an order. They can be executed simultaneously (in parallel) or in other orders. These adjusted schemes are equivalent to the technical schemes described in this application, and therefore will also fall within the scope of protection of this application.

[0078] So far, the technical solution of the present application has been described in conjunction with an embodiment shown in the accompanying drawings, but it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present application.

Claims

1. A voltage and current combined transformer, characterized in that: The voltage-current combined transformer comprises: a first functional module, a second functional module, and an optical fiber transmission line, wherein: The first functional module is used to generate a collection signal, and send the collection signal and power supply energy to the second functional module through the optical fiber transmission line, and receive the voltage or current signal of the circuit to be tested transmitted by the second functional module through the optical fiber transmission line, and convert it for reading by an external device; The second functional module is used to receive the collection signal and power supply energy from the first functional module, obtain the voltage or current signal of the circuit to be tested based on the collection signal, and transmit the collected voltage or current signal of the circuit to be tested to the first functional module through the optical fiber transmission line.

2. The voltage and current combined transformer according to claim 1, characterized in that: The optical fiber transmission line includes a first transmission line and a second transmission line; the first functional module includes a control module, a laser emission module, a collection signal receiving module, a power supply input port, a grounding port and a signal output port; The control module is used to generate an acquisition signal, and send the acquisition signal and the power supply energy from the power supply input port to the laser emission module, and obtain the voltage or current signal of the circuit to be tested sent by the acquisition signal receiving module, and convert the voltage or current signal and output it through the signal output port.

3. The voltage and current combined transformer according to claim 2, characterized in that: The laser emission module is used to receive the collection signal and power supply energy from the control module, convert the collection signal and power supply energy into corresponding optical signals and optical energy respectively, and transmit the optical signals and optical energy to the second functional module through the second transmission line.

4. The voltage-current combined transformer according to claim 3, characterized in that: The second functional module includes a photoelectric conversion module, a signal processing module and a collection module; The photoelectric conversion module is used to obtain the optical signal and optical energy, and convert the optical signal and optical energy into a collection signal and power supply electric energy respectively, send the collection signal to the signal processing module, and use the power supply electric energy to power the signal processing module.

5. The voltage-current combined transformer according to claim 4, characterized in that: The signal processing module includes a clock module, a chip selection module, a data synchronization module, an analog-to-digital conversion module, and a sampling and amplification module; The clock module is used to obtain the acquisition signal, convert the acquisition signal into a clock signal, and send the clock signal to the chip selection module, the data synchronization module and the analog-to-digital conversion module respectively; and / or, The chip selection module is used to obtain the clock signal, convert the clock signal into a chip selection signal, and send the chip selection signal to the analog-to-digital conversion module.

6. The voltage-current combined transformer according to claim 5, characterized in that: The sampling and amplifying module is used to obtain the analog signal of the circuit to be tested collected by the collecting module, amplify the analog signal, and send the amplified analog signal to the analog-to-digital conversion module; and / or, The analog-to-digital conversion module is used to obtain the clock signal, the chip select signal and the amplified analog signal, convert the amplified analog signal into a digital signal based on the clock signal and the chip select signal, and send the digital signal to the data synchronization module; and / or, The data synchronization module is used to obtain the clock signal, convert the digital signal into an optical signal based on the clock signal, and send the optical signal to the acquisition signal receiving module through the first transmission line.

7. The voltage-current combined transformer according to claim 5, characterized in that: The acquisition module includes a voltage acquisition module; the voltage acquisition module includes a first voltage dividing element, a second voltage dividing element and a third voltage dividing element connected in series; The voltage acquisition module is used to divide the voltage of the circuit to be tested using the first voltage divider element, the second voltage divider element and the third voltage divider element when the acquisition signal is the acquisition voltage, so that the sampling and amplification module acquires the analog signal at both ends of the second voltage divider element after the voltage division.

8. The voltage-current combined transformer according to claim 5, characterized in that: The acquisition module comprises a current acquisition module; the current acquisition module is used to acquire the analog signal of the circuit to be tested and send it to the sampling and amplification module when the acquisition signal is the acquisition current.

9. The voltage-current combined transformer according to claim 6, characterized in that: The acquisition signal receiving module is used to receive the optical signal sent by the data synchronization module, convert the optical signal into a voltage or current signal of the circuit to be tested, and send the voltage or current signal of the circuit to be tested to the control module.

10. A control method for a voltage and current combined transformer, characterized in that: The method is performed based on the voltage-current combined transformer according to any one of claims 1 to 9, and the method comprises: The first functional module generates a collection signal, and sends the collection signal and power supply energy to the second functional module through an optical fiber transmission line; The second functional module collects a voltage or current signal of the circuit to be tested based on the collected signal, and sends the voltage or current signal to the first functional module through an optical fiber transmission line; The first functional module obtains the voltage or current signal through the optical fiber transmission line, converts the voltage or current signal, and outputs the converted signal.

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