An adjustable phase large current generator

Abstract

The application discloses a large-current generator with adjustable phase, comprising: a main circuit module, the topology structure of the main circuit module adopts a multistage IGBT inverter; a phase control module, the phase control module inputs a power grid voltage signal through a voltage transformer, adopts a SOGI-PLL structure to improve signal tracking accuracy, combines virtual synchronous machine technology to enhance system balance, and dynamically adjusts an output signal by using an adaptive control strategy to realize phase control and synchronization; an electromagnetic compatibility optimization module, the electromagnetic compatibility optimization module adopts a layered shielding design, combines optical fiber transmission control signals, and improves equipment electromagnetic compatibility; a relay protection test integrated module, the relay protection test integrated module comprises a differential protection test mode and a distance protection test mode; the application solves the problems of low phase regulation accuracy, poor synchronization stability and insufficient electromagnetic compatibility of the large-current generator under the new energy grid-connected environment.

Description

Technical Field

[0001] This invention relates to the technical field of measuring electrical variables, and more particularly to the technical field of devices that provide reference values ​​in measuring instruments, specifically an adjustable phase high current generator. Background Technology

[0002] Currently, the increasing demand for renewable energy has led to the large-scale integration of new energy equipment such as wind power and solar photovoltaic power generation. This has changed the structure and operating characteristics of the power grid, including increased stability of the power system, power quality, and complexity of protection and control strategies. A high-current generator is a device used to generate high current, typically operating on the principle of step-down and current-up. It uses a transformer to convert the low-voltage, high-current input into the required high-current output, primarily used for testing, calibration, and experimentation of electrical equipment. However, to address the changes in grid characteristics brought about by the integration of new energy sources, its design needs corresponding optimization to adapt to the new demands.

[0003] After new energy equipment is connected to the power grid, its randomness and intermittency may cause power fluctuations in the grid, affecting grid stability. At the same time, the grid connection of new energy equipment through power electronic converters may introduce harmonics, affecting power quality. To address this, a high-current generator is needed to enhance synchronization stability in the face of grid fluctuations, simulate the grid characteristics after new energy equipment is connected to the grid, and enable the high-current generator to automatically adjust output parameters according to grid conditions and the operating status of new energy equipment to achieve optimized control and test and optimize power equipment.

[0004] Therefore, it is necessary to improve the existing high-current generators to solve the above problems. Summary of the Invention

[0005] This invention overcomes the shortcomings of the prior art and provides an adjustable phase high current generator, aiming to solve the problems of low phase adjustment accuracy, poor synchronization stability and insufficient electromagnetic compatibility of traditional high current generators caused by changes in grid characteristics after new energy sources are connected to the grid.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: an adjustable phase high current generator, comprising:

[0007] The main circuit module, whose topology adopts a multi-stage IGBT inverter, includes: a modular multilevel inverter or a parallel IGBT bridge structure;

[0008] A phase control module, which receives the grid voltage signal through a voltage transformer; the phase control module includes: an input unit, a control unit, and an output unit.

[0009] The input unit uses a SOGI-PLL structure combining a second-order generalized integrator and a digital phase-locked loop to process the grid voltage signal; the control unit, based on the grid voltage phase information provided by the SOGI-PLL structure, adjusts the frequency and phase of the output signal through virtual synchronous machine technology, and then monitors the changes in system parameters in real time through an adaptive control strategy, adjusting the virtual inertia parameter according to the changes in load impedance; the output unit generates control signals based on the adjusted parameters to control the main circuit module.

[0010] An electromagnetic compatibility optimization module, wherein the electromagnetic compatibility optimization module adopts optical fiber transmission and layered shielding, including a magnetic shielding layer and a conductive shielding layer;

[0011] The relay protection test integration module includes a differential protection test mode and a distance protection test mode.

[0012] In a preferred embodiment of the present invention, the multi-stage IGBT inverter improves the output current capacity by connecting multiple IGBT modules in parallel, and uses IGBT modules with a withstand voltage ≥1700V and a current ≥500A.

[0013] In a preferred embodiment of the present invention, the IGBT module is equipped with a water cooling system, the water cooling system having a flow rate ≥10L / min, thermal resistance <0.02℃ / W, junction temperature <120℃, and the output copper busbar having a built-in hollow water channel.

[0014] In a preferred embodiment of the present invention, the phase control module further includes a temperature compensation unit, which monitors the operating temperature of the IGBT module in real time and compensates the phase control signal according to the temperature change.

[0015] In a preferred embodiment of the present invention, the magnetic shielding layer adopts a 2mm thick Mu-metal shell to suppress interference from low-frequency magnetic fields, with an attenuation of ≥35dB.

[0016] In a preferred embodiment of the present invention, the conductive shielding layer uses a conductive shielding layer with a copper mesh coverage of ≥95%, combined with a conductive coating, to suppress high-frequency radiation with an attenuation of ≥45dB.

[0017] In a preferred embodiment of the present invention, when the relay protection test integrated module detects an abnormal load, it blocks the IGBT pulse within 5μs and quickly cuts off the output.

[0018] In a preferred embodiment of the present invention, the phase control module uses a combination of a closed-loop Hall sensor and a Rogowski coil for current feedback. The closed-loop Hall sensor is used for measuring low-frequency and DC currents, and the Rogowski coil is used for measuring high-frequency currents. The sensor error is dynamically corrected through a data fusion algorithm.

[0019] In a preferred embodiment of the present invention, the relay protection test integration module can automatically generate two large currents with a phase difference adjustable from 0° to 360° under differential protection test to simulate faults inside / outside the zone; under distance protection test, the voltage-current phase angle can be continuously adjusted from 0° to 90° to simulate impedance changes after new energy equipment is connected to the power grid.

[0020] In a preferred embodiment of the present invention, the busbar of the main circuit module adopts a multilayer copper busbar design, the distance between the conductive layers is less than 100μm, and the insulating material is one of polypropylene, cross-linked polyethylene and polyimide film, in order to reduce electromagnetic noise and interference.

[0021] This invention addresses the shortcomings of the prior art and has the following beneficial effects:

[0022] (1) This invention provides a high-current generator with adjustable phase. The main circuit module adopts a multi-stage IGBT inverter topology to achieve high current output and flexible phase adjustment. The phase control module combines SOGI-PLL structure and virtual synchronous machine technology to improve phase tracking accuracy and system stability. The electromagnetic compatibility optimization module reduces electromagnetic interference through layered shielding design and fiber optic isolated communication. The relay protection test integration module supports multiple protection test modes to ensure the comprehensiveness and practicality of the equipment.

[0023] (2) This invention combines the SOGI-PLL structure of the phase control module with virtual synchronous machine technology. The phase control module significantly improves the tracking accuracy of the grid voltage signal through the SOGI-PLL structure, effectively filters out high-frequency noise and harmonics, extracts the fundamental component, and ensures the accuracy of phase tracking. The virtual synchronous machine technology starts from the system stability, and enhances the internal stability of the high current generator when a large number of new energy devices are connected by simulating the inertia and damping characteristics of the synchronous generator. It effectively avoids the synchronization instability problem that may occur in traditional digital phase-locked loop technology. Although VSG technology may have a certain impact on the response speed while enhancing stability, the high tracking speed of the SOGI-PLL structure makes up for this deficiency. The two complement each other and jointly optimize the system performance. Compared with the existing technology, it further achieves the effect of maintaining high-precision phase control and stable output in complex grid environments.

[0024] (3) This invention employs a layered shielding design in its electromagnetic compatibility optimization module, including a magnetic shielding layer and a conductive shielding layer. Combined with fiber optic transmission of control signals, this effectively suppresses electromagnetic interference. The magnetic shielding layer suppresses low-frequency magnetic field interference, while the conductive shielding layer suppresses high-frequency radiation interference. The layered shielding design shields electromagnetic interference from different frequency bands, and fiber optic transmission blocks ground loop interference, thus improving the electromagnetic compatibility of the equipment. Furthermore, the busbar of the main circuit module adopts a stacked copper busbar design. Through the layered shielding design, fiber optic isolated communication, and the stacked copper busbar design of the main circuit module, a multi-layered electromagnetic compatibility strategy from the inside to the outside is formed. Compared with existing technologies, this further achieves the effect of stable operation in complex electromagnetic environments and a significant reduction in electromagnetic interference.

[0025] (4) This invention achieves high-precision phase control and synchronization by organically combining the SOGI-PLL structure, virtual synchronous machine technology, adaptive control strategy, and real-time temperature correction compensation through the phase control module. The SOGI-PLL structure starts from the tracking signal to ensure the accuracy of phase tracking. The virtual synchronous machine technology improves system stability and enhances system inertia and damping. The adaptive control strategy ensures dynamic adjustment of the output and achieves a balance between dynamic performance and stability. The three aspects of tracking signal, improving system stability, and ensuring dynamic adjustment of output achieve high-precision phase control and synchronization, forming a complete content control system for a high current generator, which significantly improves the performance and reliability of the high current generator in the new energy grid-connected environment.

[0026] (5) This invention employs a combination of a closed-loop Hall sensor and a Rogowski coil through current feedback, and performs signal processing using a data fusion algorithm. The closed-loop Hall sensor is used for measuring low-frequency and DC currents, while the Rogowski coil is used for measuring high-frequency currents. The combination of the two ensures high-precision measurement even under different current ranges and complex electromagnetic environments. Compared with existing technologies, this further improves the measurement accuracy and anti-interference capability of the equipment. Especially after new energy equipment is connected to the power grid, it can effectively cope with current fluctuations and electromagnetic interference, ensuring the stable operation of the equipment. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a structural diagram of a preferred embodiment of the present invention. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0031] Application Overview:

[0032] Traditional high-current generators often employ power frequency transformer current boosting or LC resonant voltage boosting technologies, which suffer from technical bottlenecks such as low phase adjustment accuracy and slow dynamic response. Especially in grid scenarios with high penetration of new energy equipment, existing equipment struggles to track dynamic changes in grid impedance in real time, leading to inaccurate fault current phase simulation. When expanding capacity in parallel, they use a simple master-slave control strategy, which suffers from large current sharing deviations and low synchronization accuracy, failing to meet the phase consistency requirements of differential protection dual-side injection. Furthermore, traditional equipment commonly uses a direct parallel copper busbar structure, resulting in insufficient electromagnetic interference suppression capabilities, with conducted emissions >30dBμV, affecting the reliability of high-precision measurement systems.

[0033] This application combines SOGI-PLL structure, virtual synchronous machine technology, and adaptive control strategy to sense changes in the equivalent impedance of the power grid in real time and dynamically adjust the output characteristics, achieving phase adjustability and improving the power grid adaptability of the equipment. Through the magnetic-electric layered shielding structure, the problem of high-frequency radiation interference during high current output is solved, significantly improving the electromagnetic compatibility of the equipment.

[0034] Exemplary device structure:

[0035] like Figure 1 As shown, by organically combining the main circuit module, phase control module, electromagnetic compatibility optimization module and relay protection test integration module, an adjustable phase high current generator is provided, which solves the impact of grid characteristic changes caused by the connection of new energy equipment to the grid on the performance of traditional high current generators.

[0036] The main circuit module is used to realize the transmission, distribution and control of electrical energy. After the new energy equipment is connected to the grid, the operating characteristics of the grid change. A high current generator is required to output high current and flexibly adjust the phase to simulate the grid characteristics after the new energy equipment is connected.

[0037] The main circuit module uses a multi-stage IGBT inverter topology, specifically a modular multilevel inverter or a parallel IGBT bridge structure. This topology enables high current output and flexible phase adjustment; it can output currents of ≤10kA; it can meet the needs of new energy equipment for high current and phase adjustment after being connected to the grid, ensuring stable operation of the equipment in complex grid environments.

[0038] New energy equipment connected to the grid via power electronic converters introduces harmonics, affecting power quality. Modular multilevel inverters achieve high voltage and high current output through multiple IGBT modules. Each module can be independently controlled to generate multiple output voltage levels, which are closer to a sine wave, thereby reducing harmonic content and improving power quality. Parallel IGBT bridge structures increase output current capacity through the parallel connection of multiple IGBT modules, while achieving flexible control through phase adjustment. Preferably, IGBT modules with a withstand voltage ≥1700V and a current ≥500A are used, such as the Infineon FF450R17ME4. The IGBT modules are equipped with a water-cooling system with a flow rate ≥10L / min, thermal resistance <0.02℃ / W, junction temperature <120℃, and the output copper busbar has a built-in hollow water channel.

[0039] To further improve the quality of the output waveform, high-frequency PWM modulation technology was adopted, and the switching frequency was...

[0040] With a frequency of ≥50kHz, combined with an LC filter with a cutoff frequency of 1.5kHz, high-frequency harmonics can be effectively filtered out, keeping the total harmonic distortion rate below 0.5%. High-frequency PWM modulation not only improves the quality of the output waveform and reduces harmonic distortion, but also further improves the quality of power. The LC filter plays a role in filtering out high-frequency harmonics, ensuring the waveform quality of the output current.

[0041] This design also employs multi-winding coupled output, superimposing current through magnetic coupling to significantly improve output capacity; by superimposing the output currents of multiple parallel modules through magnetic coupling, high current output is achieved.

[0042] The main circuit module's busbar adopts a multilayer copper busbar design to reduce the high voltage spikes generated by the IGBT during switching transients. The multilayer copper busbar design consists of several conductive layers stacked together, with insulating material added between each layer to reduce the busbar's inductance. The low inductance design reduces the generation of electromagnetic noise and the impact of electromagnetic interference on the system. Specifically, the distance between the conductive layers is less than 100μm; the insulating material is one of polypropylene, cross-linked polyethylene, and polyimide film.

[0043] The phase control module is used to achieve high-precision phase control and synchronization. After new energy equipment is connected to the grid, it enhances synchronization stability in the face of changes in grid characteristics. It simulates the grid characteristics after the new energy equipment is connected to the grid, and enables the high current generator to automatically adjust the output parameters according to the grid status and the operating conditions of the new energy equipment, thereby achieving optimized control and testing and optimizing the power equipment.

[0044] The phase control module inputs the grid voltage signal through a voltage transformer and uses the digital phase-locked loop (PLL) technology commonly used in existing technologies to achieve phase tracking. This application uses a second-order generalized integrator (SOGI) to achieve phase tracking, forming an SOGI-PLL structure. The second-order generalized integrator constructs a filter structure, receives a sinusoidal input signal, and outputs two mutually orthogonal signals. These two signals can be used to accurately extract the amplitude, frequency, and phase information of the input signal.

[0045] SOGI is used to filter and integrate grid voltage signals, effectively filtering out high-frequency noise and harmonics, and extracting the fundamental component of the grid voltage. This further solves the harmonic problems that easily occur in the grid after new energy equipment is connected to the grid. By filtering out harmonics, the SOGI-PLL structure can more accurately track the phase of the grid voltage, improving the accuracy of phase tracking.

[0046] However, with the integration of a large number of new energy sources into the power grid, due to the time characteristics of new energy equipment, multi-timescale interaction and multi-machine interaction between equipment are prone to causing grid-connected system stability problems, which can easily lead to synchronization instability of digital phase-locked loop technology. To solve the above problems, this application combines virtual synchronous machine technology and adaptive control strategy on the basis of the above to improve the synchronization efficiency of high current generator and maintain the system balance point.

[0047] Synchronization instability problems in new energy grid-connected systems can be summarized into the following three categories:

[0048] 1. Under certain operating conditions, the system may not have a stable equilibrium point, leading to synchronization instability;

[0049] 2. Even if the system has an equilibrium point, it may not be able to remain stable when subjected to small disturbances, leading to synchronization instability;

[0050] 3. When system parameters or operating conditions change, the system may not be able to smoothly transition to a new equilibrium point, leading to synchronization instability.

[0051] Therefore, maintaining this equilibrium point is crucial. Virtual synchronous machine (VSG) technology is a control strategy that simulates the dynamic characteristics of a synchronous generator, enhancing the system's inertia and damping. This allows the system to maintain its equilibrium point even when connected to a large number of energy devices and the load increases, thereby improving system stability and anti-interference capabilities. By simulating the rotation equations of a synchronous generator, VSG technology enables new energy devices to provide inertial and damping support similar to that of a traditional synchronous generator, thus enhancing system stability and avoiding the synchronization instability issues encountered with digital phase-locked loop (PLL) technology. The inertia model formula for VSG is: Where J is the virtual inertia, P m For mechanical power, P e ω is the electrical power, ω is the rotor angular velocity, ω s Where ω is the synchronous angular velocity and δ is the power angle;

[0052] The formula for calculating the virtual impedance voltage drop of VSG is: V out =V ref -Z v I, where V out V is the output voltage. ref Z is the reference voltage. v I is the virtual impedance, and I is the output current.

[0053] The phase control module, through its SOGI-PLL structure, significantly improves the tracking accuracy of the grid voltage signal, effectively filtering out high-frequency noise and harmonics, extracting the fundamental component, and ensuring accurate phase tracking. Virtual synchronous machine (VSG) technology addresses system stability by simulating the inertia and damping characteristics of a synchronous generator, enhancing the internal stability of the high-current generator when connected to a large number of new energy devices. This effectively avoids the synchronization instability problems that may occur with traditional digital phase-locked loop (PLL) technology. Although VSG technology may slightly affect response speed while enhancing stability, the high tracking speed of the SOGI-PLL structure precisely compensates for this deficiency. The two technologies complement each other, jointly optimizing system performance.

[0054] For output current control, the phase control module employs an adaptive control strategy, monitoring system parameter changes in real time. Based on load impedance changes, and in cases of large system load fluctuations, adaptive inertia control adjusts the virtual inertia parameter J in real time to achieve a balance between dynamic performance and stability. The formula for adaptive inertia control is: J ad =J0+k p (P ref -P e ), where J ad For adaptive inertia, J0 is the initial inertia, and k p P is the proportionality coefficient. refThe reference power ensures that the high current generator can maintain stable output performance when facing complex power grid environments and fluctuations in new energy equipment.

[0055] The aforementioned current feedback employs a combination of a closed-loop Hall sensor and a Rogowski coil. The closed-loop Hall sensor is used for measuring low-frequency and DC currents, while the Rogowski coil is used for measuring high-frequency currents. The signals from both sensors are integrated through signal processing. The closed-loop Hall sensor features high accuracy, fast response, and low thermal drift, while the Rogowski coil offers advantages such as non-contact measurement, wide measurement range, and strong anti-interference capability. The combination of the two ensures that high-accuracy measurements can be maintained even in different current ranges and complex electromagnetic environments.

[0056] By employing data fusion algorithms, such as Kalman filtering, the signals from the closed-loop Hall sensor and the Rogowski coil are fused, enabling dynamic correction of sensor errors and achieving high-precision positioning and measurement. in, This represents the estimation of the state vector at times k, k-1, i.e., the final state estimate and the prediction of the current state; K k For Kalman gain, z k To determine the degree of confidence in the difference between the measured and predicted values ​​at time k, This is a prediction of the measured value at time k.

[0057] Because adaptive control adjusts the IGBT module's on-state voltage, real-time temperature correction is used to compensate for the phase shift caused by voltage changes, further improving the stability and testing accuracy of phase control. Specifically, this is achieved by using a temperature sensor, such as a PT100, to enhance phase control stability. The real-time temperature correction formula is: δ c =δ m -k t (T-T0), where δ c For the compensated phase, δ m For the measured phase, k t Here, T is the temperature compensation coefficient, and T0 is the current temperature and the reference temperature, respectively.

[0058] The phase control module organically combines the SOGI-PLL structure, virtual synchronous machine technology, adaptive control strategy, and real-time temperature correction compensation. The SOGI-PLL structure starts with tracking the signal to ensure the accuracy of phase tracking. The virtual synchronous machine technology improves system stability and enhances system inertia and damping. The adaptive control strategy ensures dynamic adjustment of the output, achieving a balance between dynamic performance and stability. These three aspects, from tracking the signal, improving system stability, and ensuring dynamic adjustment of the output, achieve high-precision phase control and synchronization, forming a complete internal control system for the high-current generator. This significantly improves the performance and reliability of the high-current generator in the context of new energy grid connection.

[0059] Electromagnetic compatibility optimization modules are used to improve the anti-interference capability and electromagnetic compatibility of equipment, ensuring that the equipment can still operate stably in complex electromagnetic environments. New energy equipment such as wind power generation and solar photovoltaic power generation equipment are connected to the grid through power electronic converters, which will generate high-frequency electromagnetic interference and affect power quality. By suppressing electromagnetic interference, the stable operation of the equipment can be ensured.

[0060] Specifically, the magnetic shielding layer of the high current generator is located on the inner layer of the device, close to the internal circuitry. It is made of a 2mm thick shell of high permeability material such as Mu-metal, which can suppress interference from low-frequency magnetic fields from 50Hz to 1kHz with an attenuation of ≥35dB. The conductive shielding layer is located on the outer layer of the magnetic shielding layer and is in direct contact with the external environment. It uses a conductive shielding layer with a copper mesh coverage of ≥95% and is combined with a conductive coating. This can effectively suppress high-frequency radiation above 1MHz with an attenuation of ≥45dB.

[0061] The main function of the magnetic shielding layer is to shield low-frequency magnetic fields. Low-frequency magnetic fields have strong penetrating power, so they need to be placed close to the internal circuitry of the equipment to reduce their impact. The main function of the conductive shielding layer is to shield high-frequency electromagnetic waves. High-frequency electromagnetic waves have weak penetrating power, so placing them on the outer layer can effectively block external high-frequency interference and protect the internal circuitry.

[0062] In addition, during signal transmission, control signals are transmitted through optical fibers, such as Avago AFBR-1521Z optical fiber communication. Optical fiber transmission has high anti-interference capability and can effectively block ground loop interference, ensuring stable transmission of control signals in complex electromagnetic environments.

[0063] The electromagnetic compatibility (EMC) optimization module employs a layered shielding design and fiber optic isolated communication, enhancing the device's anti-interference capability and EMC. Furthermore, the main circuit module's busbar utilizes a multi-layered copper busbar design. Through this combination of layered shielding, fiber optic isolated communication, and the multi-layered copper busbar design of the main circuit module, a multi-layered EMC strategy is formed, extending from the internal to the external. These strategies work together to significantly improve the device's anti-interference capability and EMC.

[0064] The relay protection test integration module supports multiple protection test modes, ensuring the comprehensiveness and practicality of the equipment. After the integration of new energy sources, this module can simulate the complex operating conditions of new energy equipment connected to the power grid, and conduct comprehensive testing of the relay protection device.

[0065] Specifically, under differential protection testing, it automatically generates two large currents with a phase difference that can be adjusted from 0° to 360° to simulate faults inside / outside the zone; after the access of new energy sources, it can simulate the fault characteristics of new energy equipment after it is connected to the grid; under distance protection testing, the voltage-current phase angle can be continuously adjusted from 0° to 90°, and after the access of new energy sources, it can simulate the impedance changes of new energy equipment after it is connected to the grid.

[0066] After the new energy source is connected, when an abnormal load is detected, the IGBT pulse is blocked within 5μs, and the output is quickly cut off in the case of overcurrent to protect the safety of equipment and personnel. At the same time, it can record the current, voltage and phase data 1 second before and after the fault, with a sampling rate of 100kHz, to provide detailed data support for fault analysis.

[0067] This invention provides an adjustable-phase high-current generator by organically combining a main circuit module, a phase control module, an electromagnetic compatibility optimization module, and a relay protection testing integration module. It addresses the impact of grid characteristic changes caused by the connection of new energy equipment to the grid on the performance of traditional high-current generators. Compared with existing technologies, this invention achieves significant improvements and enhancements in high current output, flexible phase adjustment, harmonic reduction, improved power quality, phase control accuracy, system stability, electromagnetic compatibility, testing capabilities, and measurement accuracy, significantly improving the performance and reliability of the equipment in new energy grid-connected environments.

[0068] For the aforementioned equipment, tests were conducted to demonstrate the high synchronization and electromagnetic interference resistance performance of the present invention:

[0069] Experimental Example 1:

[0070] The synchronization performance of the present invention and a traditional high-current generator was tested under different proportions of new energy equipment access conditions. The traditional high-current generator uses power frequency transformer current boosting or LC resonant voltage boosting technology.

[0071] The high-current generator of this invention and a conventional high-current generator are respectively connected to a power grid simulator; a new energy equipment simulator is used to simulate the connection of different proportions of new energy equipment to the power grid (20%, 40%, 60%); the power grid simulator is set to generate the same power grid voltage signal, including fundamental and harmonic components; the output current and phase of the equipment are recorded using an oscilloscope and a power analyzer.

[0072] Table 1. Impact of the proportion of connected new energy devices on synchronization.

[0073]

[0074] The high-current generator of this invention has higher phase tracking accuracy and smaller phase difference between the output current and the grid voltage when different proportions of new energy equipment are connected.

[0075] This invention employs an SOGI-PLL structure and a virtual synchronous generator (VSG) technology. The SOGI-PLL structure effectively filters out high-frequency noise and harmonics, extracts the fundamental component, and ensures accurate phase tracking. VSG technology enhances system stability by simulating the inertia and damping characteristics of a synchronous generator, maintaining the system's equilibrium point and preventing synchronization instability even as the proportion of renewable energy equipment increases. The phase control module of this invention, combined with an adaptive control strategy, can monitor changes in system parameters in real time and adjust the virtual inertia parameters according to changes in load impedance, achieving a balance between dynamic performance and stability. Therefore, the high-current generator of this invention can maintain high-precision phase control even with varying proportions of renewable energy equipment connected.

[0076] Experimental Example 2:

[0077] The electromagnetic interference resistance of this invention and traditional high-current generators were tested under different proportions of new energy equipment access conditions; traditional high-current generators use power frequency transformer current boosting or LC resonant voltage boosting technology.

[0078] The high-current generator of this invention and a conventional high-current generator are respectively connected to a power grid simulator; a new energy equipment simulator is used to simulate the connection of different proportions of new energy equipment to the power grid (20%, 40%, 60%); electromagnetic interference sources are arranged around the equipment to generate high-frequency electromagnetic interference signals, such as high-frequency signals above 1MHz; the output current and phase of the equipment are recorded using an oscilloscope and a power analyzer.

[0079] Table 2. Impact of the Proportion of Connected New Energy Equipment on Electromagnetic Interference Resistance

[0080]

[0081]

[0082] The high-current generator of the present invention has smaller output current and phase fluctuations and stronger anti-interference ability when connected to new energy devices in different proportions.

[0083] This invention employs a layered shielding design, including a magnetic shielding layer and a conductive shielding layer, which effectively suppresses interference from low-frequency magnetic fields. Furthermore, control signals are transmitted via optical fiber, effectively blocking ground loop interference and ensuring stable transmission of control signals in complex electromagnetic environments. The main circuit module's busbar uses a multilayered copper busbar design, reducing high voltage spikes generated by the IGBTs during switching transients, lowering the busbar inductance, and reducing electromagnetic noise generation. These design optimizations significantly improve the equipment's anti-interference capability.

[0084] Based on the preferred embodiments of the present invention described above, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A high-current generator with adjustable phase, characterized in that, Includes modules: The main circuit module, whose topology adopts a multi-stage IGBT inverter, includes: a modular multilevel inverter or a parallel IGBT bridge structure; A phase control module, which receives the grid voltage signal through a voltage transformer; the phase control module includes: an input unit, a control unit, and an output unit. The input unit uses a SOGI-PLL structure combining a second-order generalized integrator and a digital phase-locked loop to process the grid voltage signal; the control unit, based on the grid voltage phase information provided by the SOGI-PLL structure, adjusts the frequency and phase of the output signal through virtual synchronous machine technology, and then monitors the changes in system parameters in real time through an adaptive control strategy, adjusting the virtual inertia parameter according to the changes in load impedance; the output unit generates control signals based on the adjusted parameters to control the main circuit module. An electromagnetic compatibility optimization module, wherein the electromagnetic compatibility optimization module adopts optical fiber transmission and layered shielding, including a magnetic shielding layer and a conductive shielding layer; The relay protection test integration module includes a differential protection test mode and a distance protection test mode.

2. The adjustable phase high current generator according to claim 1, characterized in that: The multi-stage IGBT inverter increases the output current capacity by connecting multiple IGBT modules in parallel, and uses IGBT modules with a withstand voltage of ≥1700V and a current of ≥500A.

3. The adjustable phase high current generator according to claim 2, characterized in that: The IGBT module is equipped with a water-cooling system with a flow rate ≥10L / min, thermal resistance <0.02℃ / W, junction temperature <120℃, and the output copper busbar has a built-in hollow water channel.

4. The adjustable phase high current generator according to claim 1, characterized in that: The phase control module also includes a temperature compensation unit, which monitors the operating temperature of the IGBT module in real time and compensates the phase control signal according to temperature changes.

5. A high-current generator with adjustable phase according to claim 1, characterized in that: The magnetic shielding layer uses a 2mm thick Mu-metal shell to suppress interference from low-frequency magnetic fields, with an attenuation of ≥35dB.

6. A high-current generator with adjustable phase according to claim 1, characterized in that: The conductive shielding layer uses a copper mesh coverage of ≥95% and is combined with a conductive coating to suppress high-frequency radiation with an attenuation of ≥45dB.

7. A high-current generator with adjustable phase according to claim 1, characterized in that: When the relay protection test integrated module detects an abnormal load, it blocks the IGBT pulse within 5μs and quickly cuts off the output.

8. A high-current generator with adjustable phase according to claim 1, characterized in that: The phase control module uses a combination of a closed-loop Hall sensor and a Rogowski coil for current feedback. The closed-loop Hall sensor is used for measuring low-frequency and DC currents, while the Rogowski coil is used for measuring high-frequency currents. The sensor error is dynamically corrected through a data fusion algorithm.

9. A high-current generator with adjustable phase according to claim 1, characterized in that: The relay protection test integration module can automatically generate two large currents with a phase difference adjustable from 0° to 360° under differential protection test to simulate faults inside / outside the zone; under distance protection test, the voltage-current phase angle can be continuously adjusted from 0° to 90° to simulate the impedance change after new energy equipment is connected to the grid.

10. A high-current generator with adjustable phase according to claim 1, characterized in that: The main circuit module's busbar adopts a stacked copper busbar design, with the distance between conductive layers less than 100μm. The insulating material is one of polypropylene, cross-linked polyethylene, and polyimide film to reduce electromagnetic noise and interference.

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