Sensing system and method for monitoring electromagnetic environment in converter valve

Abstract

The invention discloses a sensing system and method for monitoring an electromagnetic environment in a converter valve, and the system comprises a sensor probe which is disposed in the converter valve, is close to a to-be-detected IGBT module, is not directly electrically connected with a current loop of the to-be-detected IGBT module, and monitors the pulse current and magnetic field changes through the Faraday's law of electromagnetic induction; the data processing device comprises an AD sampling module, an FPGA control panel and an optical fiber transmitter, the input end of the AD sampling module is connected with the sensor probe, and the output end of the AD sampling module is connected with the FPGA control panel; a data input pin of the optical fiber emitter is connected with a serial port sending pin of the FPGA control board, and an output end of the optical fiber emitter is connected to a central control board in the converter valve through an optical fiber. The invention aims to solve the problems that the existing converter valve health state detection means lacks on-line monitoring means for the problems of device dynamic characteristic change and external electromagnetic intrusion, part of the detection methods are tedious in test process and high in application cost, the sensor manufacturing process is complicated, the influence of converter valve internal environment factors is caused, and the detection accuracy is high. And online monitoring of the health state of the internal device of the converter valve is difficult to realize.

Description

Technical Field

[0001] The present invention belongs to the technical field of electromagnetic sensing and relates to a sensing system and method for monitoring the electromagnetic environment inside a converter valve. Background Art

[0002] Large-capacity power electronics are currently core equipment for renewable energy integration and long-distance high-voltage direct current (HVDC) transmission. As the voltage and capacity of DC transmission lines increase, the number of converter valve components and system complexity also increase, posing significant challenges to the long-term operational reliability of power electronics systems. As core equipment for UHVDC transmission, the health of converter valves, based on large-capacity power electronics, directly impacts the stability and reliability of grid operations.

[0003] Currently, real-time assessment of the health status of converter valves relies on data monitoring methods targeting the valve's internal components. However, existing detection methods, such as IGBT fault detection methods based on pulse coupled response, IGBT module junction temperature monitoring methods based on fiber Bragg grating sensors, and ultra-high frequency methods, primarily use methods such as thermally sensitive electrical parameters to monitor the aging status of power devices. There are no corresponding online monitoring methods for issues such as changes in the device's dynamic characteristics and external electromagnetic intrusion. Furthermore, some existing detection methods suffer from drawbacks such as cumbersome testing procedures, high application costs, complex sensor manufacturing processes, and the influence of other environmental factors within the converter valve, making it difficult to achieve online monitoring of the health status of the components within the converter valve. Summary of the Invention

[0004] In response to the problems existing in the prior art, the present invention provides a sensing system and method for monitoring the internal electromagnetic environment of a converter valve. The purpose is to solve the problems existing in the existing means of detecting the health status of the converter valve, namely, the lack of online monitoring means for the dynamic characteristics changes of the device and external electromagnetic intrusion, and the difficulty in achieving online monitoring of the health status of the internal devices of the converter valve due to cumbersome testing procedures, high application costs, complex sensor manufacturing processes, and the influence of internal environmental factors of the converter valve.

[0005] In order to solve the above technical problems, the present invention is implemented through the following technical solutions:

[0006] According to a first aspect of the present invention, a sensing system for monitoring the internal electromagnetic environment of a converter valve is provided, comprising:

[0007] The sensor probe is installed inside the converter valve and close to the IGBT module to be tested. The sensor probe has no direct electrical connection with the current loop of the IGBT module to be tested and monitors the pulse current and magnetic field changes based on Faraday's law of electromagnetic induction.

[0008] The data processing device includes an AD sampling module, an FPGA control board and an optical fiber transmitter. The input end of the AD sampling module is connected to the sensor probe, and the output end is connected to the FPGA control board; the data input pin of the optical fiber transmitter is connected to the serial port sending pin of the FPGA control board, and the output end is connected to the central control board inside the converter valve via an optical fiber.

[0009] In a possible implementation of the first aspect, the sensor probe is a B-dot probe type, which is composed of two turns of copper coils printed on two sides of a circuit board.

[0010] In a possible implementation of the first aspect, the circuit board thickness of the sensor probe is 1 mm to 2 mm, the coil diameter of each side is 5 mm to 7 mm, the wire width is 0.3 mm to 0.7 mm, and the circuit board size is 300 mm. 2 ~500mm 2 .

[0011] In a possible implementation of the first aspect, the FPGA control board is of model EP4CE10F17C8N and is configured with a FIFO memory with a capacity of 4096×16 bits, for realizing synchronous processing of sampled data and serial port transmission.

[0012] In a possible implementation of the first aspect, the AD sampling module uses an AD9268 chip as its core, has a sampling rate of 125 MHz, and outputs 16-bit sampling values.

[0013] In a possible implementation of the first aspect, the optical fiber transmitter converts the data processed by the FPGA control board into an optical signal, and transmits the optical signal to the central control board inside the converter valve via the optical fiber, thereby realizing real-time transmission of electromagnetic environment data.

[0014] According to a second aspect of the present invention, a method for monitoring the electromagnetic environment inside a converter valve is provided, using the aforementioned sensor system for monitoring the electromagnetic environment inside a converter valve, comprising the following steps:

[0015] (S1) The sensor probe is fixed in a position close to the IGBT module to be tested in the converter valve, and the data processing device is installed on the surface of the metal inner shell of the converter valve;

[0016] (S2) connecting the sensor probe and the AD sampling module through a signal transmission line;

[0017] (S3) The central control board inside the converter valve is powered on, and the sensor probe senses the electromagnetic signal and outputs it to the AD sampling module;

[0018] (S4) The AD sampling module converts the analog signal into a digital signal and transmits it to the FPGA control board;

[0019] (S5) The FPGA control board calls the FIFO memory to synchronously process the data and sends it to the optical fiber transmitter via the serial port;

[0020] (S6) The optical fiber transmitter converts the data into an optical signal and transmits it to the central control board inside the converter valve via the optical fiber to realize online monitoring of the electromagnetic environment.

[0021] In a possible implementation of the second aspect, the sensor probe is a B-dot probe type, which is composed of two turns of copper coils printed on two sides of a circuit board.

[0022] In a possible implementation manner of the second aspect, the AD sampling module performs attenuation and single-ended-to-differential conversion processing on the input signal to suppress common-mode interference and even-order harmonics.

[0023] In a possible implementation of the second aspect, the AD sampling module converts the analog signal into a 16-bit digital signal at a sampling rate of 125 MHz and transmits the signal to the FPGA control board.

[0024] Compared with the prior art, the present invention has at least the following beneficial effects:

[0025] The present invention provides a sensing system for monitoring the electromagnetic environment inside a converter valve. By installing a sensor probe inside the converter valve and in close proximity to the IGBT module to be tested, the system utilizes Faraday's law of electromagnetic induction to monitor changes in pulse current and magnetic field, enabling comprehensive monitoring of the electromagnetic environment inside the converter valve. This effectively addresses the shortcomings of existing technologies in terms of monitoring range. The sensor probe has no direct electrical connection to the current circuit of the IGBT module to be tested, thus avoiding interference and risks that may be introduced by electrical connections and improving the safety of the monitoring system. At the same time, the system also reduces the additional losses and complexity caused by electrical connections, allowing the sensing system to operate more reliably in the complex environment inside the converter valve. The sensing system of the present invention has the advantages of low cost, simple structure, and small size. The data processing module of the present invention utilizes an FPGA control board to synchronize the data sampled by the sensor probe with the serial port transmission, ensuring efficient and accurate data acquisition and transmission. At the same time, an optical fiber transmitter is used to transmit the output data of the data processing module in the form of an optical signal to the central control board inside the converter valve, enabling real-time transmission of signal data. Real-time monitoring and data transmission capabilities enable operators to obtain timely information about the electromagnetic environment within the converter valve, quickly identify potential problems, and take appropriate measures, thereby improving the valve's operational reliability. Optical fiber, with its excellent electromagnetic interference resistance, is used for data transmission, effectively preventing interference from the complex electromagnetic environment within the converter valve.

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the specific embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the specific embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 This is a schematic structural diagram of a sensor system for monitoring the internal electromagnetic environment of a converter valve according to the present invention;

[0029] Figure 2 This is the sensor probe PCB design diagram of the present invention;

[0030] Figure 3 This is a schematic diagram of the specific installation position of a sensor probe of a sensor system for monitoring the internal electromagnetic environment of a converter valve according to the present invention;

[0031] Figure 4 This is a reference pulse current test diagram of a sensor system for monitoring the internal electromagnetic environment of a converter valve according to an embodiment of the present invention;

[0032] Figure 5 1 is a diagram of a reference pulse current differential value of a sensor system for monitoring the internal electromagnetic environment of a converter valve according to an embodiment of the present invention;

[0033] Figure 6 This is a sensor signal diagram of a sensor probe test of a sensor system for monitoring the internal electromagnetic environment of a converter valve according to an embodiment.

[0034] In the figure: A-sensor probe, B-actual installation position of the sensor probe. DETAILED DESCRIPTION

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0036] Combine Figures 1 to 3As shown, an embodiment of the present invention provides a sensing system for monitoring the electromagnetic environment within a converter valve, primarily comprising a sensor probe A and a data processing device. The sensor probe is installed within the converter valve, close to the IGBT module under test. The sensor probe has no direct electrical connection to the current circuit of the IGBT module under test, and monitors pulsed current and magnetic field changes based on Faraday's law of electromagnetic induction. The data processing device includes an AD sampling module, an FPGA control board, and a fiber optic transmitter. The AD sampling module's input is connected to the sensor probe, while its output is connected to the FPGA control board. The fiber optic transmitter's data input pin is connected to the serial port transmit pin of the FPGA control board, while its output is connected via optical fiber to the central control board within the converter valve.

[0037] Preferably, the sensor probe is of the B-dot probe type. The measurement principle of the B-dot probe is the same as that of the differential Rogowski coil, both of which are coreless current transformers with a single-turn coil on the primary side and a multi-turn coil on the secondary side. There is mutual inductance between the B-dot coil and the conductor carrying the current to be measured. According to Faraday's law, when the current to be measured changes, an induced electromotive force proportional to the rate of change of magnetic flux will be generated at both ends of the coil. Compared with other commonly used electromagnetic sensors, such as Rogowski coils, B-dot probes are more suitable for use in environments such as the inside of a converter valve, which have strict requirements on volume and loop parameters. Specifically, the B-dot has a simple structure and flexible placement. When performing pulse current measurement, there is no need to pass the coil through the circuit to be measured, and there is no direct electrical connection with the current circuit. It will not change the design of the current circuit to be measured and will not introduce additional distributed parameters. Therefore, the B-dot probe is very suitable for use in situations such as the inside of a converter valve, which have strict requirements on volume and loop parameters.

[0038] Preferably, the B-dot probe is a 2-turn hollow coil printed on both sides of a circuit board with a thickness of 1mm to 2mm. The size of the circuit board is 300mm 2 ~500mm 2 Each side consists of a coil with a diameter of 5mm to 7mm, the coils are wound in the same direction, and the wire width is 0.3mm to 0.7mm.

[0039] More preferably, it is printed on both sides of a circuit board with a thickness of 1 mm. The size of the circuit board is 320 mm. 2 , 20mm long and 16mm wide. Each side consists of a 6mm diameter coil, with the same winding direction, a wire width of 0.5mm, a copper thickness of 35μm, and an SMA cable connector at the output end.

[0040] The FPGA control board used in this invention preferably features Altera's Cyclone IVEP4CE10F17C8N model. This control board accepts a 7 to 15V power supply, allowing it to conveniently draw power from the driver board when used within a converter valve. This control board is equipped with a 4096 x 16-bit FIFO memory, enabling it to accommodate systems with varying transmission rates. Furthermore, the control board's external pinout is designed for easy connection to an ADC sampling module without the need for complex wiring.

[0041] Preferably, the AD sampling module used in the present invention is based on the AD9268 chip, and its output sampling data can reach 16 bits, with high sampling accuracy and a maximum sampling rate of up to 125MHz. Since the internal operating frequency of the converter valve is concentrated in the MHz level, the AD sampling module can accurately sample the changing magnetic field inside the converter valve and the pulse current flowing through the IGBT module inside the converter valve. At the same time, the AD sampling module has a low design cost and a small size, which is suitable for special scenarios with a small space inside the converter valve. The input signal of the AD sampling module is attenuated using a π-type circuit. After the signal is attenuated, a single-ended to differential conditioning circuit is used to make the AD9268 work in a fully differential input mode, reducing the common-mode interference and even-order harmonic interference of the signal, while also realizing the sampling signal offset function. The optical fiber transmitter converts the data processed by the FPGA control board into an optical signal, which is transmitted to the central control board inside the converter valve via an optical fiber, realizing real-time transmission of electromagnetic environment data.

[0042] The sensor system for monitoring the internal electromagnetic environment of a converter valve according to the present invention is specifically as follows when used:

[0043] like Figure 3 As shown, first, secure the sensor probe to the actual sensor probe mounting location B, close to the IGBT module. Ensure there is no direct electrical connection between the sensor probe and the current loop of the IGBT module under test. Pulse current and magnetic field changes are monitored using Faraday's law of electromagnetic induction. Simultaneously, a data processing device is mounted on the metal inner shell of the converter valve.

[0044] The sensor probe and data processing device are then connected using signal transmission cables. The optical fiber and power cables leading from the data processing device are then connected to the corresponding ports on the central control board inside the converter valve. It should be understood that before these steps are completed, the program code, including the AD sampling control, FIFO memory access, and serial port transmission functions, has already been burned into the FPGA control board.

[0045] The power supply to the central control board inside the converter valve is then turned on, and the sensing system begins operating. The sensor probe senses the electromagnetic signal and outputs it to the analog-to-analog sampling module. This module converts the analog signal into a 16-bit digital signal at a 125MHz sampling rate and transmits it to the FPGA control board. The FPGA control board then uses the FIFO memory to synchronously process the data and sends it via the serial port to the fiber optic transmitter. The fiber optic transmitter converts the data into an optical signal, which is then transmitted via optical fiber to the central control board inside the converter valve. The real-time voltage data sensed by the sensor probe can then be viewed on a connected host computer, enabling online monitoring of the electromagnetic environment inside the converter valve.

[0046] like Figures 4 to 6 The figure is the relevant test result obtained by the present invention on the double pulse test platform. Since the signal sampled by the sensor probe is a differential signal, Figure 4 The reference pulse current waveform is differentiated to obtain Figure 5 , and then it can be compared and analyzed with the sensor probe detection waveform based on the time scale. Figure 6 and Figure 5 A comparison reveals that the polarity of the reference pulse current waveform after differential processing is opposite to that of the actual detected waveform, but the waveform characteristics are generally consistent. This demonstrates that the present invention can accurately measure and transmit the pulse current signal normally generated by the IGBT module within the converter valve. The signal detected by the sensor probe slightly precedes the reference pulse current signal on the time scale. This is because the cable connected to the B-dot probe is shorter than the reference Rogowski coil, shortening the signal transmission process and thus causing the lead. Furthermore, it can be observed that the signal waveform detected by the sensor probe at certain time scales (for example, at 2.2μs) is slightly inconsistent with the reference pulse current waveform after differential processing at the same time. This is because the sensor probe is subject to slight magnetic field interference from other devices within the test platform, such as the power module. This also demonstrates that the sensor system constructed by the present invention can accurately detect electromagnetic radiation that may exist within the converter valve, enabling online monitoring of the electromagnetic environment within the converter valve.

[0047] The measurement principle of the B-dot sensor probe in this embodiment is the same as that of a differential Rogowski coil, both of which are coreless current transformers with a single-turn primary and a multi-turn secondary. Mutual inductance exists between the B-dot coil and the conductor carrying the current to be measured. When the current to be measured changes, Faraday's law indicates that an induced electromotive force proportional to the rate of change of magnetic flux will be generated at both ends of the coil. Ignoring stray capacitance and the subsequent cable connection, if the coil reactance is much smaller than the equivalent loop resistance, the B-dot output signal is the differential of the current signal to be measured, i.e., it operates in differential mode. In this case, the coil gain is large, the corresponding sensing gain is also large, the output signal is strong, and it is more conducive to signal detection. Therefore, the B-dot coil of the present invention is designed to operate stably in differential mode, in which the differential of the changing current signal to be measured is converted into an induced electromotive force at both ends of the coil. The electrical signal is then transmitted to the AD sampling module, converted into a 16-bit digital signal after analog-to-digital conversion, and transmitted to the FPGA control board. The control board matches the input signal with the output serial port transmission rate through the FIFO memory, and then sends the signal to the central control board inside the converter valve through the serial port via the optical fiber transmitter. Then, the real-time sensor signal data can be viewed from the host computer, realizing online monitoring of the electromagnetic environment inside the converter valve.

[0048] The present invention realizes real-time and accurate monitoring of the electromagnetic environment inside the converter valve, solving the problems existing in the prior art such as the lack of online monitoring means for changes in the dynamic characteristics of the device and external electromagnetic intrusion, as well as the difficulty in realizing online monitoring of the health status of the internal components of the converter valve due to cumbersome testing procedures, high application costs, complex sensor manufacturing processes, and the influence of factors within the internal environment of the converter valve.

[0049] In the description of the present invention, it should be understood that the terms "upper", "lower", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0050] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0051] In the present invention, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can mean fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0052] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0053] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0054] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present invention, which are used to illustrate the technical solutions of the present invention rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the above-mentioned embodiments, ordinary technicians in this field should understand that any technician familiar with this technical field can still modify the technical solutions recorded in the above-mentioned embodiments within the technical scope disclosed by the present invention, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered by the protection scope of the present invention.

Claims

1. A sensor system for monitoring the electromagnetic environment inside a converter valve, characterized in that: include: The sensor probe is installed inside the converter valve and close to the IGBT module to be tested. The sensor probe has no direct electrical connection with the current loop of the IGBT module to be tested and monitors the pulse current and magnetic field changes based on Faraday's law of electromagnetic induction. The data processing device includes an AD sampling module, an FPGA control board and an optical fiber transmitter. The input end of the AD sampling module is connected to the sensor probe, and the output end is connected to the FPGA control board; the data input pin of the optical fiber transmitter is connected to the serial port sending pin of the FPGA control board, and the output end is connected to the central control board inside the converter valve via an optical fiber.

2. A sensor system for monitoring the internal electromagnetic environment of a converter valve according to claim 1, characterized in that: The sensor probe is a B-dot probe type, which consists of two turns of copper coils printed on both sides of the circuit board.

3. The sensor system for monitoring the internal electromagnetic environment of a converter valve according to claim 2, characterized in that: The sensor probe has a circuit board thickness of 1mm to 2mm, a coil diameter of 5mm to 7mm on each side, a wire width of 0.3mm to 0.7mm, and a circuit board size of 300mm. 2 ~500mm 2 .

4. The sensor system for monitoring the internal electromagnetic environment of a converter valve according to claim 1, characterized in that: The FPGA control board model is EP4CE10F17C8N, and is equipped with a FIFO memory with a capacity of 4096×16 bits, which is used to realize synchronous processing of sampled data and serial port transmission.

5. The sensor system for monitoring the internal electromagnetic environment of a converter valve according to claim 1, characterized in that: The AD sampling module uses the AD9268 chip as its core, has a sampling rate of 125MHz, and outputs 16-bit sampling values.

6. The sensor system for monitoring the internal electromagnetic environment of a converter valve according to claim 1, characterized in that: The optical fiber transmitter converts the data processed by the FPGA control board into an optical signal, and transmits it to the central control board inside the converter valve via the optical fiber, thereby realizing real-time transmission of electromagnetic environment data.

7. A method for monitoring the electromagnetic environment inside a converter valve, characterized in that: A sensor system for monitoring the internal electromagnetic environment of a converter valve according to any one of claims 1 to 6 comprises the following steps: (S1) The sensor probe is fixed in a position close to the IGBT module to be tested in the converter valve, and the data processing device is installed on the surface of the metal inner shell of the converter valve; (S2) connecting the sensor probe and the AD sampling module through a signal transmission line; (S3) The central control board inside the converter valve is powered on, and the sensor probe senses the electromagnetic signal and outputs it to the AD sampling module; (S4) The AD sampling module converts the analog signal into a digital signal and transmits it to the FPGA control board; (S5) The FPGA control board calls the FIFO memory to synchronously process the data and sends it to the optical fiber transmitter via the serial port; (S6) The optical fiber transmitter converts the data into an optical signal and transmits it to the central control board inside the converter valve via the optical fiber to realize online monitoring of the electromagnetic environment.

8. The method for monitoring the electromagnetic environment inside a converter valve according to claim 7, characterized in that: The sensor probe is a B-dot probe type, which consists of two turns of copper coils printed on both sides of the circuit board.

9. The method for monitoring the electromagnetic environment inside a converter valve according to claim 7, characterized in that: The AD sampling module performs attenuation and single-ended-to-differential conversion on the input signal to suppress common-mode interference and even-order harmonics.

10. The method for monitoring the electromagnetic environment inside a converter valve according to claim 7, characterized in that: The AD sampling module converts the analog signal into a 16-bit digital signal at a sampling rate of 125MHz and transmits it to the FPGA control board.

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