A multi-level active regulation method for high-power high-voltage high-frequency transformer

Abstract

This invention discloses a multi-level active control method for high-power, high-voltage, high-frequency transformers, belonging to the field of power electronic system control technology, including a method based on H... 3 A comprehensive evaluation method for the operating performance of the converter system, utilizing the converter's adjustment capability to extend H 3 The design limit of T will be H 3 Considering the entire chain of T and converter, and optimizing H through collaborative control at the device, module, and system levels. 3 The present invention improves the overall performance of the converter system and the H-type converter system. 3 Treating T as an organic whole, H is optimized using more flexible constraint boundary conditions brought about by active control. 3 T; Through real-time evaluation of H 3 The operating status of the T and converter system is monitored, and electrical variables are actively adjusted at multiple levels from device to module to system to achieve H. 3 The insulation withstand voltage characteristics, port characteristics, loss characteristics, and corresponding optimization and improvement of the converter system.

Description

Technical Field

[0001] This invention belongs to the field of power electronic system control technology, specifically relating to a multi-level active control method for high-power, high-voltage, high-frequency transformers. Background Technology

[0002] In recent years, with the rapid development of high-power, high-voltage, high-frequency switching devices and high-performance soft magnetic materials such as large-size nanocrystals, the application of high-power, high-voltage, high-frequency power conversion has become increasingly widespread. As a core component of the electromagnetic coupling link, high-power, high-voltage, high-frequency transformers are an important foundation for the development of equipment such as solid-state transformers.

[0003] H 3 The basic components, overall design, and operational performance of a high-power, high-voltage, high-frequency transformer (T) are interdependent and mutually restrictive. Existing design and control methods lack a comprehensive, end-to-end consideration, severely hindering the development of H... 3 T's overall performance is improved, and it is applied in large-scale engineering projects. Furthermore, in H... 3 The overall design of T did not consider the converter's ability to actively adjust transformer performance during operation, thus allowing for more relaxed requirements on H. 3 The design constraints of T. Therefore, it is necessary to refactor H. 3 T-optimization design approach. In terms of transformer operation control, the interaction between transformers and converters is currently limited to the integrated design stage, such as considering the converter's operating range, efficiency, and other indicators when designing parameters such as transformer leakage inductance. During operation, the transformer is simply treated as a power transmission functional unit. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a multi-level active control method for high-power, high-voltage, high-frequency transformers, breaking through the limitations of H... 3 The limits of insulating dielectric characteristics, parameter modeling and design, and active operation control are defined to fully leverage the flexible control capabilities of the converter system.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A multi-level active control method for high-power high-voltage high-frequency transformers, the control method comprising the following steps:

[0007] Step 1: Based on H 3 A comprehensive evaluation method for the operating performance of the converter system, utilizing the converter's adjustment capability to extend H 3 The design limits of T;

[0008] Step 2: H 3 Considering the entire chain of T and converter, and optimizing H through collaborative control at the device, module, and system levels. 3The overall performance of the T and converter system.

[0009] Furthermore, the comprehensive evaluation method includes the following steps:

[0010] S1. Based on the operating condition modeling of core loss, winding loss, and withstand voltage characteristics, establish dv / dt, frequency, amplitude, duty cycle, transmission power, and H. 3 Mapping of the relationship between the insulation dielectric properties and port properties;

[0011] S2. Based on the circuit topology and control strategy type, adjust H according to different waveforms dv / dt. 3 The effect of T insulation leads to H 3 Design constraint domain of T under insulation and regulation constraints;

[0012] S3. Determine the fixed and adjustable parameters of the design and constraint domain;

[0013] S4. A precise calculation model combining core loss, winding loss, and insulation characteristics, with H 3 The optimal power density, efficiency, and cost of T are optimized using a non-dominated sorting multi-objective optimization genetic algorithm with an elitist strategy to select the optimal H. 3 Design scheme T.

[0014] Furthermore, the core loss modeling in S1 is based on k h (F), b(F), k e (F), k a (F) The relationship between the four loss factors and material stress is established; the winding loss modeling is obtained by equating the transposition process of Litz wire winding to the average value of impedance at different positions to obtain the equivalent circuit of Litz wire, and then calculating the current per share of Litz wire, and then obtaining the loss per share by averaging the spatial and temporal values ​​of the magnetic field; the withstand voltage characteristic modeling is obtained by applying electrical variables to H 3 The insulation and electrical withstand properties of T are obtained by forming a set of multi-parameter functions.

[0015] Furthermore, in step two, the active control at the device level first involves selecting the oscillation voltage amplitude of the converter as H. 3 The T-port characteristic parameterization features H using partial discharge amplitude and discharge count, and dielectric loss. 3 The insulation dielectric properties are then analyzed; a comprehensive evaluation model is established with oscillation voltage amplitude, dielectric loss, and switching loss as optimization objectives, and partial discharge initiation voltage as the dv / dt constraint; subsequently, based on specific operating scenarios, parameter requirements, and H... 3The insulation and port characteristics of T determine the topology of the converter to be optimized and the set of active / passive buffer circuits, thereby deriving the constraint range of converter voltage, power, and frequency conditions. Next, combined with partial discharge constraints, the distribution range of optimization objective terms is obtained, and the entropy weight method is used to establish the optimization objective function. Multiple steady-state operating points are selected, and the weighting factor for each operating point is determined, establishing the H-value for full power and wide voltage operating range. 3 The evaluation function for insulation performance, port characteristics, and switching losses is AIM = f(dv / dt). Finally, the comprehensive evaluation function is evolved and its order reduced to improve the real-time optimization speed of dv / dt. A device-level active control scheme based on gate drive active control technology is constructed for H... 3 T is used to detect the real-time operating status of the converter, enabling real-time optimization of the dv / dt parameters.

[0016] Furthermore, in step two, the active control at the module level first establishes control variable constraints in the comprehensive evaluation model based on the port voltage and transmission power range under operating conditions, and the adjustment range and coupling relationship of switching frequency, amplitude, and duty cycle parameters; then, based on H at different temperatures... 3 The relationship between the partial discharge and breakdown characteristics of the insulating dielectric and the measurement results and relationship mapping model of the converter control variables are obtained, involving H 3 The constraints of the converter control variables for insulation / reliability are determined based on the safe operation requirements of the components in the converter, resulting in a set of constraints in the module-level comprehensive evaluation model. Secondly, based on the converter's electrical parameters and H... 3 The real-time detection results of the state variables of T are used to look up the optimization results of the module-level control variables in a table to obtain the optimization results of the control variables; finally, the system-level host computer performs H... 3 The current characteristics of T are observed, and the relevant parameters in the comprehensive evaluation model are modified based on the observation results, and the variable optimization result table is updated.

[0017] Furthermore, in step two, the active control at the system level first establishes a relationship model between the total loss of the power conversion module and the module's transmission power based on actual measurement results and a module-level comprehensive evaluation model, which serves as the basis for H... 3 The optimization objective function in the T-comprehensive evaluation model; then based on H 3 A model relating the partial discharge / breakdown characteristics of the insulating dielectric to the operational requirements of a multi-module power conversion system, such as port voltage and transmission power, is established to create a multi-H... 3 The constraint set in the T-comprehensive evaluation model; finally, based on H... 3 The real-time feedback results of T-state acquisition and observation determine the optimization level. Based on device-level dv / dt, module-level waveform variables and system-level power allocation optimization strategies, closed-loop optimization control of the corresponding physical layer is realized. At the same time, based on the feedback of the control effect, the decision layer adjusts the variable factors in the optimization model.

[0018] The beneficial effects of this invention are:

[0019] The regulation method provided by this invention breaks through H 3 Understanding the characteristics of insulating media, parameter modeling and design, and the limits of active operation control are crucial for fully leveraging the flexible control capabilities of converter systems. This is of great significance for ensuring the efficient and reliable operation of high-power, high-voltage, and high-frequency power conversion equipment and promoting the steady development of the national economy and defense science and technology.

[0020] This invention combines a converter system and H 3 Treating T as an organic whole, H is optimized using more flexible constraint boundary conditions brought about by active control. 3 T; Through real-time evaluation of H 3 The operating status of the T and converter system is monitored, and electrical variables are actively adjusted at multiple levels from device to module to system to achieve H. 3 The insulation withstand voltage characteristics, port characteristics, loss characteristics, and corresponding optimization and improvement of the converter system. Attached Figure Description

[0021] 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, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a content block diagram of the present invention;

[0023] Figure 2 For H 3 T-multi-objective optimization design flowchart;

[0024] Figure 3 Diagram of a multi-level collaborative active control scheme for devices, modules, and systems;

[0025] Figure 4 A multi-level decision-making flowchart for devices, modules, and systems;

[0026] Figure 5 This is a schematic diagram of the active control process of partial discharge. Detailed Implementation

[0027] 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.

[0028] A multi-level active control method for high-power, high-voltage, high-frequency transformers, such as... Figure 1 As shown, it includes the following steps;

[0029] Step 1: Based on H 3 A comprehensive evaluation method for the operating performance of the converter system, utilizing the converter's adjustment capability to extend H 3 The design limits of T;

[0030] Step 2: H 3 Considering the entire chain of T and converter, and optimizing H through collaborative control at the device, module, and system levels. 3 The overall performance of the T and converter system.

[0031] like Figure 2 As shown, the comprehensive evaluation method includes the following steps:

[0032] S1. Based on the operating condition modeling of core loss, winding loss, and withstand voltage characteristics, establish dv / dt, frequency, amplitude, duty cycle, transmission power, and H. 3 The relationship between the insulation dielectric properties and port properties is mapped. In core loss modeling, the influence of material stress caused by potting on core performance under actual operating conditions is considered, and the relationship between four loss factors (kh(F), b(F), ke(F), ka(F)) and material stress is established. For winding losses, the equivalent circuit of the Litz wire is obtained by equating the transposition process of the Litz wire winding to the average impedance at different positions, and then the current per share of the Litz wire is calculated. The loss per share is then obtained by averaging the spatial and temporal values ​​of the magnetic field. Regarding withstand voltage characteristics, electrical variables such as voltage frequency, waveform, amplitude, rise / fall rate, and duty cycle are mapped to H. 3 The insulation and dielectric properties of T form a multi-parameter function set; combining the above aspects, H is established. 3 The sensitive parameter system that is interconnected with the converter system.

[0033] S2. Based on the circuit topology type (resonant / non-resonant) and control strategy type (frequency modulation / phase shifting), adjust H according to different waveforms dv / dt. 3 The effect of T insulation leads to H 3 The design constraint domain under the insulation and regulation constraints of T.

[0034] S3. Determine the fixed parameters (core characteristics, etc.) and adjustable parameters (insulation distance, magnetic flux density, etc.) of the design and constraint domain.

[0035] S4. A precise calculation model combining core loss, winding loss, stray parameters, and insulation characteristics, using H 3The optimal power density, efficiency, and cost of T are optimized using a non-dominated sorting multi-objective optimization genetic algorithm with an elitist strategy to select the optimal H. 3 Design scheme T.

[0036] like Figure 3 As shown, collaborative control at the device, module, and system levels improves H 3 The overall performance of the T and converter system. For active control at the device level, the oscillation voltage amplitude of the converter is first selected as H. 3 The T-port characteristic parameterization features H using partial discharge amplitude and discharge count, and dielectric loss. 3 The insulation dielectric properties are then analyzed; a comprehensive evaluation model is established with oscillation voltage amplitude, dielectric loss, and switching loss as optimization objectives, and partial discharge initiation voltage as the dv / dt constraint; subsequently, based on specific operating scenarios, parameter requirements, and H... 3 Based on the insulation and port characteristics of T, the topology of the converter to be optimized and the set of active / passive buffer circuits are determined, and the range of constraints such as converter voltage, power, and frequency are derived. Next, combined with partial discharge constraints, the distribution range of optimization objective terms is obtained, and the optimization objective function is established using the entropy weight method. Furthermore, multiple steady-state operating points (including optimal and worst-case operating conditions) are selected, and the weighting factors for each operating point are determined to establish an H-value oriented optimization function for full power and wide voltage operating range. 3 The evaluation function for insulation performance, port characteristics, and switching losses is AIM = f(dv / dt). Finally, the comprehensive evaluation function is evolved and its order reduced to improve the real-time optimization speed of dv / dt. A device-level active control scheme based on gate drive active control technology is constructed for H... 3 T is used to detect the real-time operating status of the converter (including port voltage, current, operating temperature, and local amplitude) to achieve real-time optimization of the dv / dt parameters.

[0037] For active control at the module level, firstly, based on the port voltage and transmission power range under operating conditions, and according to the adjustment range and coupling relationship of parameters such as switching frequency, amplitude, and duty cycle, control variable constraints are established in the comprehensive evaluation model; then, based on H at different temperatures... 3 The relationship between the partial discharge and breakdown characteristics of the insulating dielectric and the measurement results and relationship mapping model of the converter control variables are obtained, involving H 3 The constraints of the converter control variables for insulation / reliability are determined based on the safe operation requirements of components such as switching devices in the converter, resulting in a set of constraints in the module-level comprehensive evaluation model. Secondly, based on the converter's electrical parameters and H... 3 Real-time detection results of state variables such as partial discharge / temperature are used to look up the optimization results of module-level control variables in a table, and finally, the system-level host computer performs H... 3The current characteristics of T are observed, and the relevant parameters in the comprehensive evaluation model are modified based on the observation results, and the variable optimization result table is updated.

[0038] For proactive control at the system level, firstly, based on actual measurement results and a module-level comprehensive evaluation model, a relationship model between the total loss of the power conversion module and the module's transmission power is established, serving as the basis for H... 3 The optimization objective function in the T-comprehensive evaluation model; then based on H 3 A model relating the partial discharge / breakdown characteristics of the insulating dielectric to the operational requirements of a multi-module power conversion system, such as port voltage and transmission power, is established to create a multi-H... 3 The constraint set in the T-comprehensive evaluation model; finally, based on H... 3 The real-time feedback results of T-state acquisition and observation determine the optimization level. Based on device-level dv / dt, module-level waveform variables and system-level power allocation optimization strategies, closed-loop optimization control of the corresponding physical layer is realized. At the same time, based on the feedback of the control effect, the decision layer adjusts the variable factors in the optimization model.

[0039] The control method of the present invention will now be described using active partial discharge control as an example. The basic decision-making process is as follows: Figure 4 As shown,

[0040] The initial operating conditions are set as follows: frequency 5kHz, voltage amplitude 2.6kV, and temperature 40℃.

[0041] According to the measurement results, the partial discharge initiation voltage is 2.8kV, therefore it will not discharge;

[0042] When an abnormal temperature rise occurs, the temperature rises to 100℃ after 30 minutes. At this time, the partial discharge initiation voltage drops to 2.56kV, which is lower than the operating voltage, and a partial discharge signal is detected.

[0043] At the initial stage of partial discharge, the discharge is relatively weak and there is no need for active control or intervention at this time.

[0044] After running for 30 minutes, the temperature rose to 140℃. As can be seen from the discharge repetition rate and cumulative discharge amplitude, the discharge intensity increased sharply and reached the warning value.

[0045] Active intervention at 60 minutes, based on Figure 3 The architecture shown enables multi-level active control of devices, modules, and systems. First, the amplitude of the oscillation voltage is used as a characterization term, and dielectric loss and switching loss are used as optimization targets to control the dv / dt of the device.

[0046] If the device-level dv / dt reaches the upper limit of the constraint, then at the module level, the core / winding / dielectric loss is used as the optimization objective function to adjust the switching frequency, amplitude, and duty cycle parameters.

[0047] If the module-level constraint limit is reached, then at the system level, the transmission power of multiple modules is adjusted with the total module loss as the optimization objective function.

[0048] Afterward, the operating temperature continued to drop to 40℃. Further reducing the operating voltage to below the partial discharge extinction voltage extinguished the discharge. After stabilizing for 15 minutes, the system returned to its initial operating state, and the discharge no longer occurred. The control procedure is as follows: Figure 5 As shown.

[0049] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0050] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A multi-level active control method for high-power high-voltage high-frequency transformers, characterized in that, The control method includes the following steps: Step 1, based on A comprehensive evaluation method for converter system operating performance, utilizing the converter's adjustment capability to expand... Design limits; Step 2, Considering the entire converter chain, optimization is achieved through collaborative control at the device, module, and system levels. and the overall performance of the converter system; The comprehensive evaluation method in step one includes the following steps: S1. Based on the operating condition modeling of core loss, winding loss, and withstand voltage characteristics, establish... Frequency, amplitude, duty cycle, transmission power and Mapping of the relationship between insulating medium properties and port properties; S2. Based on circuit topology type and control strategy type, according to different waveforms right The effect of insulation, to draw Design constraint domain under insulation and regulation constraints; S3. Determine the fixed and adjustable parameters of the design constraint domain; S4. A precise calculation model combining core loss, winding loss, and insulation characteristics, to... With power density, efficiency, and cost as optimization objectives, a non-dominated sorting multi-objective optimization genetic algorithm with an elitist strategy is used to select the optimal [factor / equilibrium]. Design scheme; In step two, the active control at the device level first involves selecting the oscillation voltage amplitude of the converter as... Port characteristic parameterization features include partial discharge amplitude and discharge count, and dielectric loss. Insulating dielectric properties; then, a comprehensive evaluation model is established with oscillation voltage amplitude, dielectric loss, and switching loss as optimization objectives, and partial discharge initiation voltage as... Constraints; secondly, based on the specific operating scenario, parameter requirements, and... The insulation and port characteristics of the converter are used to determine the topology and active / passive buffer circuit set of the converter to be optimized, and the constraint range of the converter voltage, power, and frequency conditions is derived from this. Next, combined with partial discharge constraints, the distribution range of the optimization objective terms is obtained, and the entropy weight method is used to establish the optimization objective function. Multiple steady-state operating points are selected, and the weighting factor for each operating point is determined to establish a function oriented towards full power and wide voltage operating range. Evaluation functions for insulation performance, port characteristics, and switching losses Finally, the comprehensive evaluation function is subjected to evolutionary reduction to improve its order. Real-time speed optimization, constructing a device-level active control scheme based on gate drive active control technology, for Detecting real-time operating status variables of the converter to achieve... Real-time parameter optimization; In step two, the active control at the module level first establishes control variable constraints in the comprehensive evaluation model based on the port voltage and transmission power range under operating conditions, and the adjustment range and coupling relationship of switching frequency, amplitude, and duty cycle parameters; then, based on different temperatures... The relationship between partial discharge and breakdown characteristics of the insulating dielectric and the measurement results and relationship mapping model of the converter control variables are obtained. The control variable constraints for insulation / reliability of the converter are determined based on the safe operation requirements of the components in the converter, resulting in a set of constraints in the module-level comprehensive evaluation model. Secondly, based on the converter's electrical parameters and... The real-time detection results of the state variables are used to look up the optimization results of the module-level control variables in a table, and finally the optimization results are obtained from the system-level host computer. The current characteristics are observed, and the relevant parameters in the comprehensive evaluation model are modified based on the observation results, and the variable optimization result table is updated. In step two, the active control at the system level first establishes a relationship model between the total loss of the power conversion module and the module's transmission power, based on actual measurement results and a module-level comprehensive evaluation model. The optimization objective function in the comprehensive evaluation model; then according to A model relating the partial discharge / breakdown characteristics of insulating dielectrics to the port voltage and transmission power operating requirements of multi-module power conversion systems is established. The set of constraints in the comprehensive evaluation model; finally, based on The real-time feedback results of status acquisition and observation determine the optimization level, based on the device level. The module-level waveform variables and system-level power allocation optimization strategies realize closed-loop optimization control of the corresponding physical layer. At the same time, based on the feedback of the control effect, the decision layer adjusts the variable factors in the optimization model.

2. The multi-level active control method for high-power high-voltage high-frequency transformers according to claim 1, characterized in that, The core loss modeling in S1 is based on , , , The relationship between four loss factors and material stress was established; the winding loss modeling was obtained by equating the transposition process of Litz wire winding to the average value of impedance at different positions to obtain the equivalent circuit of Litz wire, and then calculating the current per share of Litz wire, and then obtaining the loss per share by averaging the spatial and temporal magnetic fields; the withstand voltage characteristic modeling was obtained by applying electrical variables to... The insulation and electrical withstand properties are obtained by forming a multi-parameter function set.

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