Voltage oscillation optimization modulation method and system for dual-active bridge converter

Abstract

The invention discloses a dual-active bridge converter voltage oscillation optimization modulation method and system. The method comprises the following steps: acquiring a first output parameter of a target converter; establishing a first target based on the first output parameter, wherein the first target at least comprises a first oscillation amplitude; presetting a first modulation strategy, and modulating the target converter according to the first modulation strategy in combination with the first target; and obtaining a modulated second output parameter of the target converter. High-frequency voltage oscillation generated by the dual-active bridge converter in the phase shift modulation process can be remarkably reduced, and potential threats to an insulation system are reduced. Damage to insulating materials is reduced, long-term stable operation is guaranteed, and the device is particularly suitable for high-cost application scenes such as offshore wind power and the like.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and in particular to a dual active bridge converter voltage oscillation optimization modulation method and system. Background Art

[0002] In medium voltage DC systems, dual active bridge (DAB) converters have become a common isolation topology due to their high efficiency, reliability and controllability. However, the phase-shift modulation strategy of the DAB converter will induce high-frequency voltage oscillations (HFVOs) at the isolation transformer ports and inside the transformer. These high-frequency, high-amplitude voltages may pose a threat to the insulation system. Existing HFVOs suppression methods mainly include improving the design of magnetic components (such as optimizing the transformer winding structure). However, the parasitic capacitance of magnetic components is difficult to effectively reduce, especially in medium voltage DC converters, and the complex winding structure not only increases the difficulty of design and manufacturing, but also poses challenges to the insulation system. Therefore, existing methods often rely on additional hardware design, affecting system efficiency and cost.

[0003] To overcome the above problems, this paper proposes a new modulation strategy that aims to effectively suppress HFVOs while ensuring efficiency. This method does not rely on additional hardware components or complex magnetic energy storage unit design, but achieves HFVOs suppression and RMS current optimization by optimizing the modulation strategy. Specifically, this method effectively reduces HFVOs and achieves optimal RMS current under a wide range of operating conditions through a hybrid modulation strategy. It not only improves the stability of the system, but also avoids the need for additional hardware in traditional methods, effectively reducing costs and complexity. Summary of the invention

[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] In view of the above existing problems, the present invention is proposed.

[0006] Therefore, the present invention provides a dual active bridge converter voltage oscillation optimization modulation method and system, which can solve the problems mentioned in the background technology.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0008] In a first aspect, the present invention provides a dual active bridge converter voltage oscillation optimization modulation method, comprising:

[0009] Obtaining the first output parameter of the target converter;

[0010] establishing a first target based on the first output parameter, the first target comprising at least a first oscillation amplitude;

[0011] Preset a first modulation strategy, and modulate the target converter according to the first modulation strategy in combination with the first target;

[0012] The modulated second output parameter of the target converter is obtained.

[0013] As a preferred solution of the voltage oscillation optimization modulation method of the dual active bridge converter described in the present invention, it also includes:

[0014] Performing a first comparison operation on the second output parameter and the first output parameter;

[0015] The first modulation strategy is optimized according to the first comparison operation.

[0016] As a preferred solution of the voltage oscillation optimization modulation method of the dual active bridge converter described in the present invention, wherein: the first modulation strategy includes:

[0017] The first modulation strategy is an arbitrary control strategy for changing the first index of the output waveform by changing the phase shift angle within the full bridges on both sides of the target converter;

[0018] The first indicator at least includes the rising edge, falling edge and zero-point level time of the target converter output waveform.

[0019] As a preferred solution of the voltage oscillation optimization modulation method of the dual active bridge converter described in the present invention, the first modulation strategy also includes:

[0020] By adjusting the internal phase shift angle of the full bridge on both sides of the target converter, the zero level time of the full bridge output voltage on both sides of the target converter is controlled, and the internal and external phase shift angles are controlled;

[0021] Under the premise of meeting the transmission power requirement, the tube switch cut-off current is adjusted to target the rising and falling edges of the full-bridge output voltage on both sides of the converter.

[0022] As a preferred solution of the voltage oscillation optimization modulation method of the dual active bridge converter described in the present invention, the first modulation strategy also includes:

[0023] By adjusting the inner and outer phase shift angles of the full bridges on both sides of the target converter, the switching transient is made to meet the conditions and the harmonics of the full bridge output voltage of the target converter reaches a local minimum at the oscillation frequency.

[0024] As a preferred solution of the voltage oscillation optimization modulation method of the dual active bridge converter described in the present invention, the first objective includes:

[0025] In each cycle, the sum of half of the rising and falling edges of the first oscillation amplitude and the zero level time is an odd multiple of the voltage oscillation cycle.

[0026] As a preferred solution of the voltage oscillation optimization modulation method of the dual active bridge converter of the present invention, wherein: the first comparison operation includes:

[0027] The first comparison operation is used to compare the difference between the second output parameter and the first output parameter;

[0028] And judging whether the second output parameter meets the standard according to the difference.

[0029] In a second aspect, the present invention provides a dual active bridge converter voltage oscillation optimization modulation system, comprising:

[0030] A first data acquisition module, used for acquiring a first output parameter of a target converter;

[0031] a target establishing module, configured to establish a first target based on the first output parameter, wherein the first target at least includes a first oscillation amplitude;

[0032] A modulation module, configured to preset a first modulation strategy, and modulate the target converter according to the first modulation strategy in combination with the first target;

[0033] The second data acquisition module acquires the second output parameter of the modulated target converter.

[0034] In a third aspect, the present invention provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above-mentioned method when executing the computer program.

[0035] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of the method described above when executed by a processor.

[0036] Compared with the prior art, the invention has the following beneficial effects: the invention proposes a voltage oscillation optimization modulation method and system for a dual active bridge converter, obtains a first output parameter of a target converter; establishes a first target based on the first output parameter, the first target at least including a first oscillation amplitude; presets a first modulation strategy, modulates the target converter according to the first modulation strategy combined with the first target; and obtains a second output parameter of the modulated target converter. The invention can significantly reduce the high-frequency voltage oscillation generated by the dual active bridge converter during the phase shift modulation process, thereby reducing the potential threat to the insulation system. At the same time, the method does not need to rely on additional hardware components or complex magnetic energy storage unit design, thereby effectively reducing the cost and complexity while ensuring the system efficiency. In addition, by accurately controlling the inner and outer phase shift angles of the full bridges on both sides of the target converter, the output waveform can also be optimized, further improving the stability and reliability of the system. For the first time, a high-frequency oscillation suppression method based on phase shift modulation is used to effectively reduce the high-frequency voltage oscillation in the DAB converter, thereby avoiding damage to the insulation system caused by high-frequency oscillation. The method reduces the high-frequency oscillation amplitude by adjusting the AC output waveform, thereby improving the system efficiency and reliability. At the same time, it reduces damage to insulating materials and ensures long-term stable operation, which is particularly suitable for high-cost application scenarios, such as offshore wind power. This application is based on the design concept of regulating switch transients and hybrid modulation optimization, which can effectively reduce high-frequency voltage oscillations and improve the overall efficiency of the system, effectively suppress high-frequency oscillations, and reduce the effective value of current. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0038] Figure 1 A method flow chart of a dual active bridge converter voltage oscillation optimization modulation method and system provided by one embodiment of the present invention;

[0039] Figure 2 An equivalent circuit diagram of a dual active bridge of a dual active bridge converter voltage oscillation optimization modulation method and system provided by an embodiment of the present invention;

[0040] Figure 3 A full-bridge output voltage waveform diagram of a dual active bridge converter voltage oscillation optimization modulation method and system provided by an embodiment of the present invention;

[0041] Figure 4A partial enlarged diagram of the full-bridge output voltage of a dual active bridge converter voltage oscillation optimization modulation method and system provided by an embodiment of the present invention;

[0042] Figure 5 A voltage transient time and voltage oscillation relationship diagram of a dual active bridge converter voltage oscillation optimization modulation method and system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0044] Example 1

[0045] Reference Figure 1-Figure 5 , which is the first embodiment of the present invention, provides a dual active bridge converter voltage oscillation optimization modulation method and system, including:

[0046] There are some problems in the existing related technologies. For example, in medium-voltage DC systems, the phase-shift modulation strategy of the DAB converter will induce high-frequency voltage oscillations (HFVOs). These high-frequency, high-amplitude voltages may pose a threat to the insulation system. Traditional HFVOs suppression methods mainly rely on improving the design of magnetic components, such as optimizing the transformer winding structure, but this method has limitations. First, the parasitic capacitance of magnetic components is difficult to effectively reduce, especially in medium-voltage DC converters. Secondly, the complex winding structure not only increases the difficulty of design and manufacturing, but may also pose new challenges to the insulation system. Therefore, existing methods often need to rely on additional hardware design, which not only increases the complexity of the system, but may also affect the system efficiency and cost.

[0047] The present application provides a method that can effectively solve the above-mentioned problems. Next, multiple embodiments will be combined to explain in detail how to implement the voltage oscillation optimization modulation method of the dual active bridge converter;

[0048] Figure 1 A method flow chart of a dual active bridge converter voltage oscillation optimization modulation method and system is shown, comprising:

[0049] S101, obtaining a first output parameter of a target converter;

[0050] In an optional embodiment, the target converter may be a DAB converter or other types of converters;

[0051] In the embodiment of the present application, a DAB converter is selected as the target converter.

[0052] In an optional embodiment, the first output parameter may include but is not limited to key indicators such as the output voltage, output current, and oscillation amplitude of the converter. These parameters are the basis for subsequent modulation strategy design and optimization.

[0053] In the embodiment of the present application, the first output parameter includes the output waveform of the DAB converter, which includes key information such as the amplitude, frequency and waveform characteristics of the voltage oscillation. By analyzing these parameters in detail, the operating status and existing problems of the DAB converter can be further understood, providing data support for the subsequent modulation strategy design.

[0054] It should be noted that obtaining the first output parameter of the target converter can accurately understand the current operating state of the target converter, including key information such as the amplitude and frequency of voltage oscillation, etc. This information is an important basis for subsequently establishing optimization targets and designing modulation strategies.

[0055] It should also be noted that through in-depth analysis of the first output parameter, the target to be optimized can be clearly identified, such as reducing the voltage oscillation amplitude, reducing the threat of high-frequency oscillation to the insulation system, etc. At the same time, these parameters also provide a benchmark for subsequent comparison of the effects before and after modulation, thereby ensuring the effectiveness and reliability of the modulation strategy. Therefore, obtaining the first output parameter of the target converter is one of the key steps in the present invention to achieve voltage oscillation optimization modulation.

[0056] S102, establishing a first target based on a first output parameter, the first target at least including a first oscillation amplitude;

[0057] In an optional embodiment, the first target based on the first output parameter is established to clarify the optimization direction. The first target includes at least the first oscillation amplitude, because the amplitude of the high-frequency voltage oscillation is an important indicator to measure its impact. By setting a reasonable oscillation amplitude threshold, it can be used as an optimization target, aiming to reduce the actual oscillation amplitude to below the threshold by adjusting the modulation strategy, thereby reducing the potential threat to the insulation system.

[0058] In an optional embodiment, the first target may also include other indicators related to voltage oscillation, such as oscillation frequency, waveform characteristics, etc. These indicators are also of great significance for optimizing the modulation strategy.

[0059] In an optional embodiment, when setting the first goal, it is necessary to comprehensively consider factors such as the operating state of the converter, the application environment, and cost-effectiveness. On the one hand, it is necessary to ensure that the set goal is achievable to avoid being too idealistic and resulting in complex modulation strategy design and high costs; on the other hand, it is also necessary to ensure that the goal is challenging enough to promote technological innovation and performance improvement.

[0060] It should be noted that when establishing the first goal, in-depth analysis and weighing are required to ensure its scientificity and rationality.

[0061] In an optional embodiment, after the first goal is determined, a modulation strategy can be designed according to the goal. The design of the modulation strategy is the core link of the present invention to achieve voltage oscillation optimization modulation. By adjusting the control parameters of the converter, such as the phase shift angle, the switching frequency, etc., the characteristics of its output waveform can be changed, thereby achieving the purpose of suppressing high-frequency voltage oscillation.

[0062] In an optional embodiment, in the design process of the modulation strategy, the influence of factors such as the dynamic characteristics and nonlinear characteristics of the converter needs to be fully considered to ensure the effectiveness and stability of the modulation strategy. At the same time, the modulation strategy needs to be simulated and experimentally tested to verify its effect in practical applications.

[0063] In the embodiment of the present application, the first goal includes:

[0064] In each cycle, the sum of half of the rising and falling edges of the first oscillation amplitude and the zero level time is an odd multiple of the voltage oscillation cycle.

[0065] It should be noted that this setting can further refine the control of voltage oscillation characteristics and ensure that the modulation strategy has higher accuracy and effectiveness in optimizing voltage oscillation. Specifically, by adjusting the proportional relationship between the rising and falling edges of the oscillation amplitude and the zero-level time to meet a specific odd multiple condition, the waveform characteristics of the voltage oscillation can be better controlled, thereby achieving effective suppression of high-frequency voltage oscillation. This setting not only improves the flexibility of the modulation strategy, but also enhances its adaptability and stability under different working conditions.

[0066] It should also be noted that establishing a first target based on the first output parameter, where the first target at least includes the first oscillation amplitude, can provide a clear direction and basis for the formulation of subsequent modulation strategies. By accurately setting the first target, it can be ensured that the modulation strategy is targeted and effective in optimizing voltage oscillations, thereby achieving precise control of high-frequency voltage oscillations. This not only helps to improve the stability and reliability of the system, but also reduces potential threats to the insulation system while ensuring system efficiency, further extending the service life of the equipment. In addition, a clear first target also provides an important reference benchmark for the subsequent optimization and verification of the modulation strategy, which helps to promote technological innovation and performance improvement.

[0067] S103, presetting a first modulation strategy, and modulating the target converter according to the first modulation strategy and the first target;

[0068] In an optional embodiment, the first modulation strategy can be implemented based on a variety of control parameters and technical means, including but not limited to adjusting the inner phase shift angle and outer phase shift angle of the full bridges on both sides of the target converter, and controlling the switching transient.

[0069] Specifically, the adjustment of the inner and outer phase shift angles can change the waveform characteristics of the full-bridge output voltage on both sides of the target converter, including the rising edge, falling edge, zero-level time, etc., thereby effectively suppressing high-frequency voltage oscillations. At the same time, by accurately controlling the switching transient, the voltage and current stresses during the switching process can be further reduced, reducing the potential threat to the insulation system.

[0070] In an optional embodiment, when presetting the first modulation strategy, the actual operating state and application environment of the target converter need to be fully considered to ensure the effectiveness and stability of the modulation strategy. For example, in high-cost application scenarios such as offshore wind power, special attention needs to be paid to the impact of the modulation strategy on system efficiency and cost to avoid overly complex modulation strategies that lead to excessive system costs or reduced efficiency.

[0071] In an optional embodiment, the first modulation strategy can also be combined with other technical means to achieve a more optimized effect. For example, a hybrid modulation strategy can be adopted to combine phase shift modulation with other modulation methods to achieve more accurate control of output voltage and current. At the same time, advanced control algorithms and intelligent optimization technologies, such as neural networks, genetic algorithms, etc., can also be introduced to achieve adaptive optimization and intelligent adjustment of the modulation strategy.

[0072] In an optional embodiment, when implementing the first modulation strategy, it is necessary to perform real-time monitoring and feedback control on the target converter to ensure the effectiveness and stability of the modulation strategy.

[0073] Specifically, by collecting key parameters such as the output voltage and output current of the target converter and comparing and analyzing them with the preset first target, the modulation strategy can be adjusted and optimized in real time according to the analysis results. This real-time monitoring and feedback control mechanism can further improve the stability and reliability of the system and ensure the effectiveness and adaptability of the modulation strategy under different working conditions.

[0074] In the embodiment of the present application, the first modulation strategy includes:

[0075] The first modulation strategy is an arbitrary control strategy for changing the first index of the output waveform by changing the phase shift angle within the full bridges on both sides of the target converter;

[0076] The first indicator includes at least the rising edge, falling edge and zero-point level time of the target converter output waveform.

[0077] In the embodiment of the present application, the first modulation strategy further includes:

[0078] By adjusting the internal phase shift angle of the full bridge on both sides of the target converter, the zero level time of the full bridge output voltage on both sides of the target converter is controlled, and the internal and external phase shift angles are controlled;

[0079] Under the premise of meeting the transmission power requirement, the tube switch cut-off current is adjusted to target the rising and falling edges of the full-bridge output voltage on both sides of the converter.

[0080] In the embodiment of the present application, the first modulation strategy further includes:

[0081] By adjusting the inner and outer phase shift angles of the full bridges on both sides of the target converter, the switching transient is made to meet the conditions and the harmonics of the full bridge output voltage of the target converter reaches a local minimum at the oscillation frequency.

[0082] In an optional embodiment, the harmonics of the full-bridge output voltage of the target converter reach a local minimum at the oscillation frequency, which can effectively reduce the amplitude of the high-frequency voltage oscillation, thereby reducing damage to the insulation system. The design idea of ​​this modulation strategy is to achieve precise suppression of voltage oscillations by accurately controlling the switching transient and harmonic characteristics. Specifically, by adjusting the inner phase shift angle and the outer phase shift angle, the waveform characteristics of the full-bridge output voltage can be changed so that the harmonic components at the oscillation frequency reach a local minimum, thereby effectively suppressing high-frequency voltage oscillations. The advantage of this method is that it does not require additional hardware components or complex magnetic energy storage unit designs, and can achieve optimized control of voltage oscillations by adjusting control parameters alone, greatly reducing cost and complexity.

[0083] In an optional embodiment, in order to further improve the effectiveness and stability of the modulation strategy, a hybrid modulation strategy can also be adopted. The hybrid modulation strategy combines phase shift modulation with other modulation methods, such as pulse width modulation (PWM) or space vector modulation (SVM), to achieve more precise control of output voltage and current. By introducing advanced control algorithms and intelligent optimization technologies, such as neural networks and genetic algorithms, adaptive optimization and intelligent adjustment of the modulation strategy can be achieved, thereby further improving the performance and stability of the system.

[0084] It should be noted that presetting the first modulation strategy and modulating the target converter according to the first modulation strategy combined with the first target can ensure that the modulation process has a clear target orientation and strategy guidance, thereby improving the modulation effect and efficiency. Specifically, by presetting the first modulation strategy, the control parameters and technical means in the modulation process can be clarified, such as the adjustment of the inner phase shift angle, the outer phase shift angle, and the control of the switching transient. The setting and optimization of these parameters are based on the precise setting and in-depth analysis of the first target, so that the modulation strategy can be targeted and effective in optimizing voltage oscillation. At the same time, by modulating the target converter in combination with the first target, the modulation effect can be monitored and feedback controlled in real time, and the modulation strategy can be adjusted and optimized in real time according to the analysis results, thereby further improving the stability and reliability of the system. This preset modulation strategy combined with the target-oriented modulation method not only helps to improve the overall performance of the system, but also reduces the potential threat to the insulation system while ensuring the efficiency of the system, and further extends the service life of the equipment.

[0085] S104, obtaining a second output parameter of the modulated target converter.

[0086] In the embodiment of the present application, a first comparison operation is performed on the second output parameter and the first output parameter;

[0087] The first modulation strategy is optimized according to the first comparison operation.

[0088] In the embodiment of the present application, the first comparison operation includes:

[0089] The first comparison operation is used to compare the difference between the second output parameter and the first output parameter;

[0090] And determine whether the second output parameter meets the standard based on the difference.

[0091] In an optional embodiment, the second output parameter of the target converter after modulation is obtained in order to evaluate the effectiveness of the modulation strategy and optimize the modulation strategy according to the evaluation result. Specifically, the second output parameter may include but is not limited to key indicators such as the output voltage, output current, and oscillation amplitude of the converter, which can reflect the suppression effect of the modulation strategy on voltage oscillation. By comparing the output parameters before and after modulation, the optimization degree and effect of the modulation strategy can be intuitively understood, providing data support for subsequent optimization work.

[0092] In the embodiment of the present application, the second output parameter is subjected to a first comparison operation with the first output parameter in order to quantify the optimization effect of the modulation strategy. The first comparison operation may include calculating statistics such as the difference and ratio of the output parameters before and after modulation to objectively evaluate the degree of optimization of the modulation strategy. At the same time, according to the result of the first comparison operation, the first modulation strategy may be optimized. The direction of optimization may include adjusting control parameters, improving the design of the modulation strategy, etc., in order to further improve the effectiveness and stability of the modulation strategy.

[0093] In an optional embodiment, when optimizing the first modulation strategy, it is necessary to comprehensively consider multiple factors, such as system stability, efficiency, cost, etc. On the one hand, it is necessary to ensure that the optimized modulation strategy can more effectively suppress high-frequency voltage oscillations and reduce potential threats to the insulation system; on the other hand, it is also necessary to avoid overly complex modulation strategies that lead to excessive system costs or reduced efficiency. Therefore, in-depth trade-offs and analysis are required during the optimization process to ensure that the optimized modulation strategy is scientific and reasonable.

[0094] In an optional embodiment, when optimizing the first modulation strategy, advanced control algorithms and intelligent optimization technologies, such as neural networks, genetic algorithms, etc., can also be introduced. These algorithms and technologies can realize adaptive optimization and intelligent adjustment of the modulation strategy, and automatically adjust the control parameters and modulation strategy according to the real-time status and operating environment of the system, thereby further improving the performance and stability of the system. This intelligent optimization method not only helps to improve the overall performance of the system, but also reduces the dependence on manual intervention and improves the automation and reliability of the system.

[0095] It should be noted that obtaining the second output parameter of the modulated target converter and optimizing the first modulation strategy according to the comparison result is one of the key steps to achieve voltage oscillation optimization modulation. Through this step, the effectiveness and stability of the modulation strategy can be ensured, the overall performance of the system can be improved, the potential threat to the insulation system can be reduced, and the service life of the equipment can be further extended.

[0096] In summary, the present invention proposes a voltage oscillation optimization modulation method for a dual active bridge converter, obtaining a first output parameter of a target converter; establishing a first target based on the first output parameter, the first target at least including a first oscillation amplitude; presetting a first modulation strategy, modulating the target converter according to the first modulation strategy combined with the first target; and obtaining a second output parameter of the modulated target converter. The method can significantly reduce the high-frequency voltage oscillation generated by the dual active bridge converter during the phase shift modulation process, thereby reducing the potential threat to the insulation system. At the same time, the method does not need to rely on additional hardware components or complex magnetic energy storage unit designs, thereby effectively reducing costs and complexity while ensuring system efficiency. In addition, by accurately controlling the inner and outer phase shift angles of the full bridges on both sides of the target converter, the output waveform can also be optimized, further improving the stability and reliability of the system. For the first time, a high-frequency oscillation suppression method based on phase shift modulation is used to effectively reduce the high-frequency voltage oscillation in the DAB converter, thereby avoiding damage to the insulation system caused by high-frequency oscillation. The method reduces the high-frequency oscillation amplitude by adjusting the AC output waveform, thereby improving system efficiency and reliability. At the same time, it reduces damage to insulating materials and ensures long-term stable operation, which is particularly suitable for high-cost application scenarios, such as offshore wind power. This application is based on the design concept of regulating switch transients and hybrid modulation optimization, which can effectively reduce high-frequency voltage oscillations and improve the overall efficiency of the system, effectively suppress high-frequency oscillations, and reduce the effective value of current.

[0097] Example 2

[0098] In a preferred embodiment, Figure 2 As shown in FIG. 1 , the DAB converter includes a primary full bridge, a magnetic cavity and a secondary full bridge circuit. The magnetic cavity includes a parasitic network of a transformer and a phase-shifting inductor. In the figure, the transformer is illustrated by taking a typical 2:1 transformer as an example. rk (k=1~6) represents the self-inductance of different areas of the transformer, R rk (k=1~6) represents the AC resistance of the winding in different regions. ab contains abundant high-frequency harmonics, which are triggered by the resonance effect of the magnetic cavity, thus forming the primary transformer port voltage u Mport The high-frequency voltage oscillation shown in the figure. High-frequency voltage oscillation not only appears in the terminal voltage, but also appears inside the transformer, such as the interlayer voltage u at the center of the primary winding. mid This voltage oscillation is manifested as a decaying high-frequency sinusoidal voltage superimposed on a square wave, the amplitude of which can far exceed the port voltage, and the frequency is fixed, which is the series resonant frequency f of the magnetic cavity. s .

[0099] The proposed method reduces the included frequency f by changing the AC output voltage waveform. sThe harmonic content near Figure 3 As shown, the primary AC output voltage is u ab , the AC output voltage of the secondary side is u cd , the inductor current is i L， Figure 4 yes Figure 3 The switching transient partial enlargement diagram consists of three parts. First, at t 0 At the moment when switch S2 is turned off, the inductor current charges the parasitic capacitance of S2 and discharges the parasitic capacitance of S1, thus achieving the soft turn-on of S2. This corresponds to the voltage rise time t r1 , between t1 and t2, S1 and S2 are turned on, and the zero level time is t ph , between t2 and t3, S3 is closed, the inductor current discharges the parasitic capacitance of S3 and charges the parasitic capacitance of S4, realizing the soft opening of S4, corresponding to the voltage rise time t r2. Due to t ph The zero level time can be changed by adjusting the switching interval of the full-bridge pair tube, and the voltage rise time can be changed by adjusting the phase shift angle to change the inductor current. Therefore, the proposed method can change the duration of the transient process;

[0100] like Figure 5 As shown, the duration of the transient process t is defined as rh =0.5*(t r1 +t r2 +t ph ). By optimizing the modulation, tph is changed to half the voltage oscillation period by k times. Assuming the oscillation period is T s (T s =1 / f s ), then t rh =0.5kT s , k = 1, 3, 5, ..., the frequency of the AC output voltage can be f s The harmonic content reaches a minimum, making the voltage oscillation amplitude reach a local optimum.

[0101] Since k only needs to be close to an odd number, its possible values ​​are large, so there is potential for optimizing other objectives. Therefore, the optimization goal of the proposed patent is to optimize the effective value of the inductor current with t rh The difference from the nearby odd number is the optimization target, thereby achieving simultaneous optimization of efficiency and voltage oscillation.

[0102] Example 3

[0103] This embodiment also provides a dual active bridge converter voltage oscillation optimization modulation system, including:

[0104] A first data acquisition module, used for acquiring a first output parameter of a target converter;

[0105] A target establishing module, configured to establish a first target based on the first output parameter, wherein the first target at least includes a first oscillation amplitude;

[0106] A modulation module, used for presetting a first modulation strategy, and modulating the target converter according to the first modulation strategy and the first target;

[0107] The second data acquisition module acquires the second output parameter of the modulated target converter.

[0108] The above-mentioned unit modules may be embedded in or independent of a processor in a computer device in the form of hardware, or may be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to the above-mentioned modules.

[0109] This embodiment also provides a computer device, which can be a terminal. The computer device includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, an operator network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a voltage oscillation optimization modulation method of a dual active bridge converter is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a key, trackball or touchpad set on the housing of the computer device, or an external keyboard, touchpad or mouse.

[0110] This embodiment further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the following steps are implemented:

[0111] Obtaining the first output parameter of the target converter;

[0112] establishing a first target based on the first output parameter, the first target comprising at least a first oscillation amplitude;

[0113] Preset a first modulation strategy, and modulate the target converter according to the first modulation strategy combined with the first target;

[0114] The modulated second output parameter of the target converter is obtained.

[0115] Example 4

[0116] In a preferred embodiment, a specific implementation step of a dual active bridge converter voltage oscillation optimization modulation method is also provided, specifically:

[0117] (1) By optimizing the internal phase shift angle, the AC output waveform of the converter is adjusted to effectively reduce the high-frequency voltage oscillation caused by modulation.

[0118] (2) The high-frequency harmonic amplitude is optimized by internal phase shifting, and a number of optional switching transient times are obtained according to the oscillation period. Under the optional switching transient time, the high-frequency voltage oscillation reaches a minimum value, ensuring the stability of the system under different working conditions.

[0119] (3) During the optional low-oscillation switching transient time, the effective value of the inductor current is optimized, thereby improving system efficiency under the premise of low voltage oscillation.

[0120] Specifically, the modulation strategy is adjusted to control the amplitude and oscillation of high-frequency harmonics, thereby suppressing high-frequency voltage oscillations (HFVOs). The specific process is as follows:

[0121] The high-frequency voltage oscillation amplitude is included in the optimization target. The phase shift angle in the full bridges on both sides of the DAB is changed by the controller to adjust the output waveform of the DAB converter, thereby affecting its harmonic content and oscillation degree; the rising edge, falling edge and zero-point level time of the AC output waveform of the DAB converter are adjusted;

[0122] By adjusting the internal phase shift angle of the full-bridge, controlling the zero-level time of the full-bridge output voltage, and controlling the internal and external phase shift angles, the tube switch cut-off current, the rising edge and falling edge of the full-bridge output voltage are adjusted while meeting the transmission power requirements;

[0123] By adjusting the inner and outer phase shift angles of the full bridges on both sides of the DAB, the switching transient is satisfied and the harmonics of the full bridge output voltage reach a local minimum at the oscillation frequency, which can significantly reduce high frequency oscillation.

[0124] The optimization goal of the full-bridge output voltage is that in each cycle, the sum of half of the rising and falling edges and the zero-level time is an odd multiple of the voltage oscillation period;

[0125] By optimizing the full-bridge output voltage waveform and the efficiency at the same time, the appropriate zero-level time and voltage rise and fall edges are selected according to the voltage and transmission power on both sides of the DAB;

[0126] In order to realize hardware control, the optimization results are applied to the actual system using the lookup table method to optimize the inductor RMS current and harmonic content under different working conditions.

[0127] As an optimization solution, the present invention controls the waveform of the output voltage and accurately controls the amplitude of high-frequency oscillation by introducing a switching transient regulation method, so as to effectively avoid high-frequency voltage oscillation caused by switching transient changes under wide range operation.

[0128] The present invention uses a numerical optimization algorithm to calculate the phase shift adjustment strategy under different working conditions offline, and applies it to hardware control through a lookup table method, thereby achieving real-time suppression of high-frequency oscillation.

[0129] Through the above technical scheme, the present invention not only solves the problem that high-frequency voltage oscillations are difficult to suppress in the prior art, but also improves system performance without increasing additional hardware costs, providing an efficient and reliable solution for medium-voltage DC systems and high-cost application scenarios (such as offshore wind power, etc.).

[0130] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

[0131] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiments of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0132] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0133] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0134] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0135] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0136] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A voltage oscillation optimization modulation method for a dual active bridge converter, characterized in that: include: Obtaining the first output parameter of the target converter; establishing a first target based on the first output parameter, the first target comprising at least a first oscillation amplitude; Preset a first modulation strategy, and modulate the target converter according to the first modulation strategy in combination with the first target; The modulated second output parameter of the target converter is obtained.

2. The voltage oscillation optimization modulation method of the dual active bridge converter according to claim 1, characterized in that: Also includes: Performing a first comparison operation on the second output parameter and the first output parameter; The first modulation strategy is optimized according to the first comparison operation.

3. The voltage oscillation optimization modulation method of the dual active bridge converter according to claim 2, characterized in that: The first modulation strategy includes: The first modulation strategy is an arbitrary control strategy for changing the first index of the output waveform by changing the phase shift angle within the full bridges on both sides of the target converter; The first indicator at least includes the rising edge, falling edge and zero-point level time of the target converter output waveform.

4. The voltage oscillation optimization modulation method of the dual active bridge converter according to claim 3, characterized in that: The first modulation strategy also includes: By adjusting the internal phase shift angle of the full bridge on both sides of the target converter, the zero level time of the full bridge output voltage on both sides of the target converter is controlled, and the internal and external phase shift angles are controlled; Under the premise of meeting the transmission power requirement, the tube switch cut-off current is adjusted to target the rising and falling edges of the full-bridge output voltage on both sides of the converter.

5. The voltage oscillation optimization modulation method of the dual active bridge converter according to claim 4, characterized in that: The first modulation strategy also includes: By adjusting the inner and outer phase shift angles of the full bridges on both sides of the target converter, the switching transient is made to meet the conditions and the harmonics of the full bridge output voltage of the target converter reaches a local minimum at the oscillation frequency.

6. The voltage oscillation optimization modulation method of the dual active bridge converter according to claim 5, characterized in that: The first objective includes: In each cycle, the sum of half of the rising and falling edges of the first oscillation amplitude and the zero level time is an odd multiple of the voltage oscillation cycle.

7. The voltage oscillation optimization modulation method of the dual active bridge converter according to claim 6, characterized in that: The first comparison operation includes: The first comparison operation is used to compare the difference between the second output parameter and the first output parameter; And judging whether the second output parameter meets the standard according to the difference.

8. A dual active bridge converter voltage oscillation optimization modulation system, characterized in that: include: A first data acquisition module, used for acquiring a first output parameter of a target converter; a target establishing module, configured to establish a first target based on the first output parameter, wherein the first target at least includes a first oscillation amplitude; A modulation module, configured to preset a first modulation strategy, and modulate the target converter according to the first modulation strategy in combination with the first target; The second data acquisition module acquires the second output parameter of the modulated target converter.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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