A universal transient dc offset rejection method for phase-shifted control isolated converter

Abstract

The application belongs to the technical field of power electronics, and specifically discloses a general transient DC bias suppression method for a phase-shift control isolation type converter, which comprises the following steps: when transient DC bias caused by updating of a phase-shift ratio parameter of the phase-shift control isolation type converter is detected, monitoring data of the phase-shift ratio parameter before and after the updating and original and auxiliary side voltage parameters are input into a volt-second balance compensation model to obtain a target compensation amount output by the volt-second balance compensation model; and the target compensation amount is used to adjust a drive pulse width of the original side full-bridge circuit in a subsequent switching cycle to eliminate the transient DC bias; and the volt-second balance compensation model is determined by using a compensation variable parameter corresponding to the introduced target compensation amount to analyze contribution of volt-second area changes of the energy storage inductor generated by the original and auxiliary side full-bridge circuits in a transition switching cycle. According to the application, the transient DC bias can be quickly eliminated, and the converter can be smoothly transitioned to a new steady state within about half a switching cycle.

Description

Technical Field

[0001] This application belongs to the field of power electronics technology, specifically relating to the field of large-scale power grid security technology, and more specifically, relating to a general transient DC bias suppression method for phase-shift control isolated converters. Background Technology

[0002] Against the backdrop of the rapid development of the global energy internet and DC distribution networks, phase-shift controlled isolated converters, such as dual active bridge (DAB) converters, have become the core conversion topology in energy storage systems, electric vehicle charging stations, and power electronic transformers due to their significant advantages, including bidirectional power flow capability, inherent soft-switching characteristics, high power density, and electrical isolation. In practical operation, converters typically employ phase-shift modulation technology to meet diverse power regulation requirements by adjusting phase-shift parameters in real time. However, when the system dynamically updates phase-shift parameters in response to power changes, the abrupt change in phase angle inevitably introduces transient DC bias into the energy storage inductor current. This transient current offset can have serious negative impacts, including causing high-frequency transformer core saturation, increasing circuit power losses, and causing abnormal heating of magnetic components, thus greatly threatening the safety and efficiency of converter operation.

[0003] Currently, most existing strategies for suppressing transient DC bias rely on mathematical models established for specific modulation modes (such as those for single-phase shifting or specific multi-phase shifting schemes). These models are computationally complex, cannot achieve volt-second balance in the shortest time, and have a long suppression and adjustment process, resulting in low efficiency in suppressing transient DC bias.

[0004] Therefore, how to better suppress the transient DC bias generated by phase-shift controlled isolated converters has become a technical problem that the industry urgently needs to solve. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this application is to better suppress the transient DC bias generated by the phase-shift control isolated converter, and to solve the problem of low efficiency in the suppression of transient DC bias in the existing strategy.

[0006] To achieve the above objectives, in a first aspect, this application provides a general transient DC bias suppression method for phase-shift controlled isolated converters, comprising: When a transient DC bias is detected caused by an update of the phase shift parameter of the phase-shift controlled isolated converter, the monitoring data of the phase shift parameter before and after the update and the primary and secondary voltage parameters are input into the volt-second balance compensation model to obtain the target compensation amount output by the volt-second balance compensation model; the phase-shift controlled isolated converter includes primary and secondary full-bridge circuits and an energy storage inductor; Using the target compensation amount, the driving pulse width of the primary-side full-bridge circuit is adjusted during the subsequent switching cycle to eliminate the transient DC bias. The volt-second balance compensation model is determined by using the compensation variable parameters corresponding to the introduced target compensation amount to analyze the contribution of the primary and secondary full-bridge circuits to the volt-second area change of the energy storage inductor during the transition switching cycle.

[0007] Optionally, before inputting the data of the shift ratio parameter and the primary and secondary voltage parameters before and after the update into the volt-second balance compensation model, the method further includes: Based on the original bridge inward shift ratio before and after the update and the compensation variable parameters corresponding to the target compensation amount, the first volt-second contribution component model is determined; the first volt-second contribution component model is used to determine the volt-second contribution component of the primary full-bridge circuit to the energy storage inductor during the transition switching cycle. Based on the power flow state, and the secondary bridge in-bridge shift ratio parameters and inter-bridge shift ratio parameters before and after the update, a second volt-second contribution component model is determined; the second volt-second contribution component model is used to determine the volt-second contribution component generated by the secondary full-bridge circuit to the energy storage inductor during the transition switching cycle; the shift ratio parameters include the primary bridge in-bridge shift ratio parameters, the secondary bridge in-bridge shift ratio parameters, and the inter-bridge shift ratio parameters; Based on the first volt-second contribution component model and the second volt-second contribution component model, a volt-second balance analysis is performed to determine the volt-second balance compensation model.

[0008] Optionally, determining the first volt-second contribution component model based on the original side bridge inward displacement comparison parameters before and after the update and the compensation variable parameters corresponding to the target compensation amount includes: Based on the switching cycle parameters, primary voltage amplitude parameters, and the comparison parameters of the primary bridge inward shift before and after the update, the volt-second area deviation term model is determined. Based on the switching cycle parameters, the primary voltage amplitude parameters, and the compensation variable parameters, a volt-second area controllable term model is determined. Based on the volt-second area deviation term model and the volt-second area controllable term model, the first volt-second contribution component model is obtained.

[0009] Optionally, the step of determining the second volt-second contribution component model based on the power flow direction state and the comparison parameters of the secondary bridge inward movement and the inter-bridge movement before and after the update includes: When the power flow state is in a non-power reversal state or a power reversal state, the corresponding volt-second contribution component quantum model is determined based on the secondary voltage amplitude parameter, the switching cycle parameter, and the secondary bridge inward shift ratio parameter and the bridge inter-shift ratio parameter before and after the update. The second volt-second contribution component model is obtained based on each of the aforementioned volt-second contribution component sub-models.

[0010] Optionally, the step of determining the corresponding volt-second contribution component quantum model under each operating condition based on the secondary voltage amplitude parameter, the switching cycle parameter, and the secondary bridge inward shift ratio parameter and the inter-bridge shift ratio parameter before and after the update includes: Using the secondary voltage amplitude parameter, the switching cycle parameter, and the previous secondary bridge inward shift ratio parameter and bridge inter-shift ratio parameter, the previous secondary volt-second area contribution analysis was performed to obtain the corresponding first volt-second contribution component quantum model under each operating condition. Using the secondary voltage amplitude parameter, the switching cycle parameter, and the updated secondary bridge inward shift ratio parameter and bridge inter-shift ratio parameter, an updated secondary volt-second area contribution analysis is performed to obtain the corresponding second volt-second contribution component sub-model under each operating condition; the volt-second contribution component sub-model includes the first volt-second contribution component sub-model and the second volt-second contribution component sub-model.

[0011] Optionally, the phase-shift controlled isolated converter includes, but is not limited to, a single-phase dual active bridge converter, a three-phase dual active bridge converter, a cascaded dual active bridge converter, or an AC-DC isolated converter.

[0012] Secondly, this application provides a general transient DC bias suppression device for phase-shift controlled isolated converters, comprising: The transient compensation calculation module is used to input the monitoring data of the phase shift ratio parameter before and after the update and the primary and secondary voltage parameters into the volt-second balance compensation model when a transient DC bias is caused by an update of the phase shift ratio parameter of the phase-shift controlled isolated converter. The module obtains the target compensation amount output by the volt-second balance compensation model. The phase-shift controlled isolated converter includes primary and secondary full-bridge circuits and an energy storage inductor. The transient compensation control module is used to adjust the driving pulse width of the primary-side full-bridge circuit in the subsequent switching cycle using the target compensation amount to eliminate the transient DC bias. The volt-second balance compensation model is determined by using the compensation variable parameters corresponding to the introduced target compensation amount to analyze the contribution of the primary and secondary full-bridge circuits to the volt-second area change of the energy storage inductor in the transition switching cycle.

[0013] Thirdly, this application provides an electronic device, comprising: at least one memory for storing a program; and at least one processor for executing the program stored in the memory, wherein when the program stored in the memory is executed, the processor is configured to execute the method described in the first aspect or any possible implementation thereof.

[0014] Fourthly, this application provides a computer-readable storage medium storing a computer program that, when run on a processor, causes the processor to perform the method described in the first aspect or any possible implementation thereof.

[0015] Fifthly, this application provides a computer program product that, when run on a processor, causes the processor to perform the method described in the first aspect or any possible implementation thereof.

[0016] It is understood that the beneficial effects of the second to fifth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here.

[0017] Overall, the technical solutions conceived in this application have the following beneficial effects compared with the prior art: This application provides a general transient DC bias suppression method for phase-shift controlled isolated converters. By utilizing the superposition theorem, the primary and secondary full-bridge circuits of the converter are equivalent to two decoupled independent square wave voltage sources. The inductor volt-second area contribution of each voltage source under arbitrary phase-shift modulation mode and power flow is calculated. During the transition period of phase-shift parameter update or switching, the volt-second balance compensation model is constructed and solved using the introduced primary-side pulse width adjustment variable. This compensates and corrects the duty cycle of the primary-side full-bridge circuit drive signal, which can quickly eliminate transient DC bias and allow the converter to smoothly transition to a new steady state within about half a switching cycle. At the same time, no additional sensors are required, which effectively improves the system's operational stability and efficiency. Attached Figure Description

[0018] Figure 1 This is one of the flowcharts illustrating the general transient DC bias suppression method for phase-shift controlled isolated converters provided in this application embodiment; Figure 2 This is a schematic diagram of the single-phase dual active bridge converter topology circuit provided in the embodiments of this application; Figure 3 These are schematic diagrams of the equivalent voltage source model and typical phase-shift modulation waveforms provided in the embodiments of this application. Among them, (a) is a schematic diagram of the equivalent model of a square wave voltage source with zero voltage level provided in the embodiments of this application, (b) is a schematic diagram of the equivalent model of a square wave voltage source without zero voltage level provided in the embodiments of this application, and (c) is a schematic diagram of the waveform of a typical phase-shift modulation mode provided in the embodiments of this application. Figure 4 This is a schematic diagram of the inductor volt-second area bias and DC bias caused by the phase shift parameter update provided in the embodiments of this application; Figure 5This is a schematic diagram of the volt-second area generated by the primary-side full-bridge circuit during the phase-shifting update process of the converter provided in this application embodiment; Figure 6 This is a schematic diagram of the principle of calculating and analyzing the volt-second area of ​​the secondary full-bridge circuit provided in the embodiments of this application. (a) is a schematic diagram of the volt-second area distribution of the secondary full-bridge circuit during the shift ratio parameter update process provided in the embodiments of this application. (b) is a schematic diagram of the classification of the secondary volt-second area calculation working conditions based on power flow direction and modulation conditions provided in the embodiments of this application. Figure 7 This is a schematic diagram illustrating the technical principle of the dual active bridge general transient DC bias suppression strategy provided in the embodiments of this application; Figure 8 This is the second flowchart illustrating the general transient DC bias suppression method for phase-shift controlled isolated converters provided in this application embodiment; Figure 9a This is a schematic diagram illustrating the effect of suppressing transient DC bias using conventional methods under the first operating condition provided in this application embodiment; Figure 9b This is a schematic diagram illustrating the effect of suppressing transient DC bias using the method of this application under the first operating condition provided in the embodiments of this application; Figure 9c This is a schematic diagram illustrating the effect of suppressing transient DC bias using conventional methods under the second operating condition provided in this application embodiment; Figure 9d This is a schematic diagram illustrating the effect of suppressing transient DC bias using the method of this application under the second operating condition provided in the embodiments of this application; Figure 9e This is a schematic diagram illustrating the effect of suppressing transient DC bias using conventional methods under the third operating condition provided in this application embodiment; Figure 9f This is a schematic diagram illustrating the effect of suppressing transient DC bias using the method of this application under the third operating condition provided in the embodiments of this application; Figure 9g This is a schematic diagram illustrating the effect of suppressing transient DC bias using conventional methods under the fourth operating condition provided in the embodiments of this application; Figure 9h This is a schematic diagram illustrating the effect of suppressing transient DC bias using the method of this application under the fourth operating condition provided in the embodiments of this application; Figure 10 This is a schematic diagram of the structure of the general transient DC bias suppression device for phase-shift controlled isolated converters provided in the embodiments of this application; Figure 11 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0020] The terms "first" and "second," etc., used in the specification and claims of this application are used to distinguish different objects, not to describe a specific order of the objects. For example, "first volt-second contribution component model" and "second volt-second contribution component model," etc., are used to distinguish different volt-second contribution component models, not to describe a specific order of the volt-second contribution component models.

[0021] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0022] In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more, for example, multiple processing units means two or more processing units, multiple elements means two or more elements, etc.

[0023] In existing technologies, to address the DC bias suppression problem, current research also provides a closed-loop feedback method based on current monitoring or magnetic flux detection. Although this method can completely eliminate the bias, it requires additional sensors, which not only increases system cost but also reduces the compactness of the control scheme. Therefore, this application provides a general transient DC bias suppression method for phase-shift controlled isolated converters.

[0024] The embodiments of this application are described below with reference to the accompanying drawings.

[0025] Figure 1 This is one of the flowcharts illustrating the general transient DC bias suppression method for phase-shift controlled isolated converters provided in this application embodiment, such as... Figure 1 As shown, it includes: Step S1: When a transient DC bias is caused by an update of the phase shift parameter of the phase-shift controlled isolated converter, the monitoring data of the phase shift parameter before and after the update and the primary and secondary voltage parameters are input into the volt-second balance compensation model to obtain the target compensation amount output by the volt-second balance compensation model; the phase-shift controlled isolated converter includes primary and secondary full-bridge circuits and an energy storage inductor; Step S2: Using the target compensation amount, adjust the driving pulse width of the primary-side full-bridge circuit in the subsequent switching cycle to eliminate transient DC bias; The volt-second balance compensation model is determined by using the compensation variable parameters corresponding to the introduced target compensation amount to analyze the contribution of the primary and secondary full-bridge circuits to the volt-second area change of the energy storage inductor in the transition switching cycle.

[0026] Specifically, in the embodiments of this application, the phase-shift controlled isolated converter includes at least primary and secondary full-bridge circuits and an energy storage inductor. For example, such as Figure 2 As shown, a single-phase DAB converter circuit includes: a primary-side input filter capacitor connected to the DC power supply. C in and secondary output filter capacitor C o The switching transistors that make up the primary-side full-bridge circuit Q 1. Q 2. Q 3. Q 4. Switching transistors that make up the secondary-side full-bridge circuit Q 5. Q 6. Q 7. Q 8. A high-frequency transformer connected between the primary-side full-bridge circuit and the secondary-side full-bridge circuit, and an energy storage inductor connected in series between the output terminal of the primary-side full-bridge circuit and the primary winding of the high-frequency transformer. L .

[0027] It is understood that the volt-second area described in the embodiments of this application is an important concept in electrical engineering used to describe the characteristics of inductive elements or pulse voltage waveforms. It is the integral of the product of voltage (volts, V) and time (seconds, s), that is, the area enclosed by the curve of voltage change over time and the time axis. It reflects the cumulative effect of voltage over time.

[0028] The displacement ratio parameter described in the embodiments of this application may specifically include the original side bridge internal displacement ratio. Compared to the inward relocation of the secondary side bridge Compared to bridge-to-bridge movement .

[0029] Among them, the original side bridge was moved inward compared to , is the ratio of the phase shift angle between the two bridge arms within the primary-side full-bridge to half a switching cycle, used to determine the duration of the zero-voltage level of the equivalent voltage source on the primary side; the phase shift ratio within the secondary-side bridge... , is the ratio of the phase shift angle between the two bridge arms within the secondary side of the full bridge to half a switching cycle, used to determine the duration of the zero-voltage level of the equivalent voltage source on the secondary side; the inter-bridge phase shift ratio The voltage amplitude at the midpoint of the primary side of the full bridge With the amplitude of the midpoint voltage of the secondary full bridge The ratio of the relative phase shift angle between the primary and secondary waveforms to half a switching cycle is used to characterize the relative time deviation between the primary and secondary waveforms and to determine the power transmission direction and magnitude of the converter.

[0030] Therefore, it is understandable that when the phase shift angle parameter is dynamically updated, it will inevitably lead to a synchronous update of the corresponding phase shift parameter, and cause a transient DC bias.

[0031] The volt-second balance compensation model described in this application is determined by analyzing the contribution of the primary and secondary full-bridge circuits to the volt-second area change of the energy storage inductor during the transition switching cycle using the compensation variable parameters corresponding to the introduced target compensation amount.

[0032] Here, the transition switching period refers to the switching period time from the start of updating the shift ratio parameter to the transition into a new steady state.

[0033] Specifically, in the embodiments of this application, the primary-side full-bridge circuit and the secondary-side full-bridge circuit of the converter are equivalent to two decoupled independent square wave voltage sources. Based on the ratio of the primary and secondary bridge inward shifts before and after the update, a compensation variable for adjusting the primary-side drive pulse width, i.e., the compensation variable parameter corresponding to the target compensation amount, is introduced to construct the volt-second contribution component model of the equivalent voltage sources of the primary and secondary sides to the energy storage inductor during the transition switching cycle. This enables the contribution analysis of the volt-second area change of the primary and secondary full-bridge circuits to the energy storage inductor during the transition switching cycle. Finally, the volt-second balance compensation model is constructed using the volt-second balance principle.

[0034] like Figure 3 Based on the superposition theorem, this application equates the primary and secondary full-bridge circuits of the phase-shift controlled isolated converter to two decoupled independent square wave voltage sources. To cover all possible phase-shift modulation conditions, two basic voltage source models are established: (1) a general model containing zero voltage level (e.g., ...). Figure 3 As shown in (a) of the diagram: When the full-bridge circuit uses internal phase-shift control (i.e., the internal phase-shift ratio is not equal to 0), the output voltage waveform exhibits a three-level characteristic (positive, negative, and zero). At this time, the duration of the positive level of the voltage source is shown in the diagram. t h and duration of negative level t l Both are affected by inward movement compared to d i The model describes the control of the inductor current. i L Piecewise linear variation characteristics under single pulse voltage excitation.

[0035] (2) Special case models without zero voltage level (e.g.) Figure 3As shown in (b) of the diagram: When the full-bridge circuit does not introduce an internal phase shift (i.e., the internal phase shift ratio is equal to 0), the zero voltage level disappears, and the output voltage degenerates into a pure square wave (50% duty cycle). This is Figure 3 Model (a) in d i The special case when =0, its positive and negative level duration is fixed at half a switching cycle.

[0036] (3) Unified mapping of modulation modes (e.g.) Figure 3 As shown in (c): The two basic models described above can fully characterize the four typical existing phase-shifting modulation modes, establishing the universality basis of the method described in this application: Single-phase-shifting (SPS) mode: No internal phase shift on either the primary or secondary side ( d 1= d 2=0), both primary and secondary voltage sources correspond Figure 3 Model (b) in the text; Extended Phase Shift (EPS) mode: one side has an internal phase shift, the other side does not (e.g., d 1≠0, d 2=0), then respectively correspond to Figure 3 (a) model and Figure 3 (b) Combination of models; Dual-phase (DPS) and Triple-phase (TPS) modes: both primary and secondary sides introduce internal phase shifts ( d 1≠0, d 2≠0), both primary and secondary voltage sources correspond Figure 3 Model (a) in the text. In summary, through... Figure 3 By decomposing the model, this application can transform the complex inductor current analysis into a linear superposition calculation of the volt-second product of two independent voltage sources.

[0037] In the embodiments of this application, in step S1, when the phase shift ratio parameter (including the phase shift ratio inside the primary bridge) of the phase-shift controlled isolated converter is detected... Compared to the inward relocation of the secondary side bridge Compared to bridge-to-bridge movement When any parameter in the model is updated, causing a transient DC bias, the monitoring data of the shift ratio parameter and the primary and secondary voltage parameters before and after the update are input into the volt-second balance compensation model constructed above, and the target compensation amount output by the volt-second balance compensation model can be obtained.

[0038] Furthermore, in the embodiments of this application, in step S2, the target compensation amount obtained in step S1 is superimposed on the pulse width modulation signal of the primary-side full-bridge circuit to control the conduction time of each switch in the primary-side full-bridge circuit, thereby adjusting the driving pulse width of the primary-side full-bridge circuit in the subsequent switching cycle, realizing the correction of the driving pulse width of the primary-side full-bridge circuit, and eliminating transient DC bias.

[0039] The aforementioned existing mathematical modeling methods for specific modulation modes have shortcomings such as poor versatility and difficulty in adapting to complex and ever-changing modulation switching scenarios or power reversal conditions.

[0040] Based on the above embodiments, as an optional embodiment, the phase-shift control isolated converter in this application includes, but is not limited to, single-phase DAB converters, three-phase DAB converters, cascaded DAB converters, or AC-DC isolated converters. The method in this application has high versatility and can adapt to the above-mentioned different types of complex and varied modulation switching scenarios or power reversal conditions.

[0041] The method in this application uses the superposition theorem to decouple and model each bridge arm. The construction of its volt-second balance compensation model is essentially based on the decoupled calculation of the energy contribution of each equivalent voltage source on the primary and secondary sides to the inductor. This logic does not depend on a specific topology phase number (e.g., single-phase, three-phase) or power flow direction (e.g., bidirectional flow). Therefore, the method described in this application can be directly extended to three-phase isolation converters and AC-DC single-stage conversion scenarios. This application uses a single-phase DAB converter as an example for description; the implementation method of this method can be derived by analogy for other phase-shift controlled isolation converter topologies.

[0042] The general transient DC bias suppression method for phase-shift controlled isolated converters provided in this application uses the superposition theorem to treat the primary and secondary full-bridge circuits of the converter as two decoupled independent square wave voltage sources. It calculates the inductor volt-second area contribution of each voltage source under arbitrary phase-shift modulation modes and power flow. During the transition period of phase-shift parameter updates or switching, it constructs and solves a volt-second balance compensation model using the introduced primary-side pulse width adjustment variable. This compensates for and corrects the duty cycle of the primary-side full-bridge circuit drive signal, quickly eliminating transient DC bias and allowing the converter to smoothly transition to a new steady state within approximately half a switching cycle. Furthermore, it eliminates the need for additional sensors, effectively improving the system's operational stability and efficiency.

[0043] Based on the above embodiments, as an optional embodiment, in step S1, before inputting the data of the shift ratio parameter and the primary and secondary voltage parameters before and after the update into the volt-second balance compensation model, the method further includes: Based on the parameters of the primary bridge inward shift before and after the update and the compensation variable parameters corresponding to the target compensation amount, the first volt-second contribution component model is determined; the first volt-second contribution component model is used to determine the volt-second contribution component of the primary full-bridge circuit to the energy storage inductor during the transition switching cycle. Based on the power flow state, and the secondary bridge in-bridge shift ratio parameters and inter-bridge shift ratio parameters before and after the update, the second volt-second contribution component model is determined; the second volt-second contribution component model is used to determine the volt-second contribution component of the secondary full-bridge circuit to the energy storage inductor during the transition switching cycle; the shift ratio parameters include the primary bridge in-bridge shift ratio parameters, the secondary bridge in-bridge shift ratio parameters, and the inter-bridge shift ratio parameters; Based on the first volt-second contribution component model and the second volt-second contribution component model, a volt-second balance analysis is performed to determine the volt-second balance compensation model.

[0044] Specifically, based on the above embodiments, the method of this application embodiment has three control degrees of freedom, the first degree of freedom being the original side bridge inward displacement ratio parameter. The first degree of freedom is used to determine the duration of the zero voltage level of the primary-side equivalent voltage source; the second degree of freedom is the ratio parameter of the secondary-side bridge inward shift. The third degree of freedom is used to determine the duration of the zero voltage level of the equivalent voltage source on the secondary side; the third degree of freedom is the inter-bridge shift ratio parameter. It is used to characterize the relative time deviation between the primary and secondary waveforms and to determine the power transmission direction and magnitude of the converter.

[0045] In the embodiments of this application, based on the phase shift ratio parameters of the primary bridge before and after the phase shift update, a compensation variable is introduced to adjust the primary driving pulse width, i.e., the compensation variable parameter corresponding to the target compensation amount. A model is constructed to analyze the volt-second contribution of the primary-side equivalent voltage source to the energy storage inductor during the transition switching cycle. Simultaneously, based on the shift ratio parameters and power flow state of the secondary bridge before and after the shift ratio update, and utilizing the symmetry or polarity mapping relationship of the DAB converter, a model is independently constructed to analyze the volt-second contribution of the secondary-side equivalent voltage source to the energy storage inductor during the transition switching cycle. The volt-second area contribution components of the primary and secondary sides are then combined to construct a balance equation that makes the total volt-second area deviation of the inductor zero during the transition cycle. This allows for the analysis of the contribution of the primary and secondary full-bridge circuits to the volt-second area change of the energy storage inductor during the transition switching cycle, ultimately constructing a volt-second balance compensation model.

[0046] like Figure 4 The inductor current waveforms during steady-state operation (shown as a dashed blue line) and phase-shift parameter updates (shown as a solid blue line) were compared. During steady-state operation, the inductor current waveform changes over one switching cycle. The net volt-second area deviation between two adjacent half-cycles is zero, and the inductor current varies periodically without DC bias. However, when the system adjusts power... When the phase shift parameters are dynamically updated in real time, this volt-second balance is disrupted. Specifically, due to the abrupt change in the phase shift angle, the inductor... to An excessively large negative volt-second area accumulates during this period. This causes the inductor current to fail to return to its initial steady-state reference value at the end of the half-cycle, resulting in a significant transient DC bias.

[0047] In the embodiments of this application, the compensation variable parameters are based on the original side bridge inward displacement comparison parameters before and after the update and the target compensation amount. Determine the model of the first volt-second contribution component of the primary-side full-bridge circuit to the energy storage inductor during the transition switching cycle. For example... Figure 5 The primary side volt-second area contribution component is determined based on the update of the phase shift parameter. Here, the model of the first volt-second contribution component corresponding to the primary side consists of two parts. The first part is the inherent bias term, which is the change in the primary side phase shift before and after the phase shift parameter jump. The first part is determined by the compensation variable parameters; the second part is the controllable adjustment term. The decision is made, and its expression satisfies .

[0048] Based on the above embodiments, as an optional embodiment, the first volt-second contribution component model is determined according to the original side bridge inward displacement comparison parameters before and after the update and the compensation variable parameters corresponding to the target compensation amount, including: Based on the switching cycle parameters, primary voltage amplitude parameters, and the comparison parameters of the primary bridge inward shift before and after the update, the volt-second area deviation term model is determined. Based on the switching cycle parameters, primary voltage amplitude parameters, and compensation variable parameters, a volt-second area controllable term model is determined. Based on the volt-second area deviation term model and the volt-second area controllable term model, the first volt-second contribution component model is obtained.

[0049] Specifically, such as Figure 5 As shown, during the transition period of parameter update compared to the shift ratio. to Within this application, compensation variable parameters are introduced. This is used to asymmetrically adjust the duty cycle of the primary-side drive signal. The volt-second area corresponding to the positive half-cycle of the primary side, when introduced Then, its duration is extended (or shortened). The volt-second area corresponding to the negative half-cycle of the primary side, when introduced Subsequently, its duration is correspondingly shortened (or lengthened). Due to the full-bridge structural characteristics of the dual active bridge, the following is introduced... This is equivalent to increasing the volt-second area in one half-cycle while decreasing the reverse volt-second area by the same magnitude in the other half-cycle, thus producing a double net adjustment effect. Therefore, the sum of the controllable volt-second areas in this part, i.e., the volt-second area controllable term model, can be expressed as:

[0050] For the inherent deviation term, this deviation is caused by the original side bridge shifting inward compared to the parameter. Jump to Directly caused by, and related to compensation variables Irrelevant. For example... Figure 5 As shown, Indicates the time. Previously, this was part of the last negative half-cycle before the phase shift update, and its waveform width was shifted from the original bridge inner phase to the parameter before the update. Decision. Under standard phase-shift modulation, the duty cycle of the effective voltage during the half-cycle including the zero level is ( - The corresponding volt-second contribution and the old phase shift angle Correlation, mathematically, corresponds to a negative contribution term ( - ). Indicates the time. Subsequently, as part of the first positive half-cycle after entering the new steady state, its waveform width shifts inward from the updated original bridge relative to the parameters. The decision, its corresponding volt-second contribution compared to the new shift Correlation, mathematically, corresponds to a positive contribution term ( - ).

[0051] In summary, in the embodiments of this application, the first volt-second contribution component model can be expressed as: ; In the formula, This indicates the phase update of the primary side (i.e., time step). The volt-second area of ​​the last negative half-cycle before ); S 12 S represents the volt-second area of ​​the positive half-cycle of the original side; 13 S represents the volt-second area of ​​the negative half-cycle on the primary side; 14 This represents the volt-second area of ​​the first positive half-cycle after the original side enters a new steady state.

[0052] here, Indicates the switching cycle parameter. This represents the primary voltage magnitude parameter. This represents the comparison parameter between the original side bridge's inward movement before and after the update. This represents a volt-second area controllable term model. This represents the volt-second area deviation term model. Therefore, based on the volt-second area deviation term model and the volt-second area controllable term model, a model for the first volt-second contribution component, used to determine the volt-second contribution component of the primary-side full-bridge circuit to the energy storage inductor during the transition switching cycle, is constructed.

[0053] Based on the above embodiments, as an optional embodiment, the second volt-second contribution component model is determined based on the power flow direction state and the comparison parameters of the secondary bridge inward and inter-bridge shift before and after the update, including: In the case of power flow state in non-power reversal state or power reversal state, the corresponding volt-second contribution component quantum model is determined based on the secondary voltage amplitude parameter, switching cycle parameter, and the secondary bridge inward shift ratio parameter and bridge inter-shift ratio parameter before and after the update. Based on the individual volt-second contribution component models, the second volt-second contribution component model is obtained.

[0054] Specifically, in the embodiments of this application, the secondary-side full-bridge circuit has different power flow states, including a non-power reversal state or a power reversal state.

[0055] More specifically, in the embodiments of this application, such as Figure 6 As shown in (a), it illustrates the volt-second area distribution generated by the secondary full-bridge circuit during the phase shift parameter update process. Figure 6 (b) in the diagram is a classification of operating conditions for calculating the secondary-side volt-second area based on power flow direction and modulation conditions. For example... Figure 6 As shown in (b), the secondary-side volt-second area contribution component is calculated based on four operating conditions according to the power flow direction and modulation parameters. For the non-power reversal state, when the inter-bridge shift ratio... Compared with the inward relocation of the secondary side bridge When the sum is less than 0.5, it is condition A1; when the inter-bridge displacement is relatively... Compared with the inward relocation of the secondary side bridge When the sum is greater than or equal to 0.5, it is operating condition A2. For the power reversal state, i.e., when the updated inter-bridge shift ratio... When the value is less than 0, the negative phase shift angle is mapped to an equivalent positive phase shift angle using the polarity mapping relationship, and then the secondary side volt-second area is calculated. Here, the polarity mapping relationship satisfies... ,in This is compared to the mapped equivalent positive bridge displacement. When the updated bridge displacement is compared... Compared to the relocation of the secondary side bridge after the update When the sum is less than 0, it is condition B1; when the updated inter-bridge displacement is compared to Compared to the updated secondary side bridge relocation When the sum is greater than 0, it is operating condition B2.

[0056] Furthermore, in the embodiments of this application, when the power flow state is in a non-power reversal state or a power reversal state, the secondary voltage amplitude parameter is used. Switching cycle parameters And the comparison of the parameters of the secondary side bridge inward movement before and after the update. Bridge displacement relative parameters Perform secondary side volt-second area contribution analysis to determine the corresponding volt-second contribution component quantum model under each operating condition.

[0057] Based on the above embodiments, as an optional embodiment, based on the secondary voltage amplitude parameters, switching cycle parameters, and the comparison parameters of the secondary bridge inward shift and the bridge-to-bridge shift before and after the update, the corresponding volt-second contribution component quantum model for each operating condition is determined, including: Using the secondary voltage amplitude parameters, switching cycle parameters, and the previous secondary bridge inward shift ratio parameters and bridge inter-shift ratio parameters, the previous secondary volt-second area contribution analysis was performed to obtain the corresponding first volt-second contribution component quantum model under each operating condition. The updated secondary-side volt-second area contribution analysis is performed using the secondary-side voltage amplitude parameters, switching cycle parameters, and updated secondary-side bridge inward shift ratio parameters and bridge-to-bridge shift ratio parameters to obtain the corresponding second volt-second contribution component sub-models for each operating condition. The volt-second contribution component sub-models include the first volt-second contribution component sub-model and the second volt-second contribution component sub-model.

[0058] Specifically, in the embodiments of this application, This represents the residual volt-second area of ​​the secondary voltage within the current half-switch cycle before the phase-shifting parameters are updated. Operating condition A1 ( At this point, the phase shift angle is relatively small, and the integration interval spans the transition point of the secondary voltage, encompassing both positive and negative voltage segments. According to the square wave integration principle, the total area equals "positive voltage duration × amplitude" minus "negative voltage duration × amplitude," that is... .

[0059] For operating condition A2 ( At this point, the phase shift angle is relatively large, and the integration interval only falls within a single-polarity voltage segment (or covers the entire pulse width). Therefore, the calculation simplifies to the integration of a single voltage segment, i.e. .

[0060] In summary, for operating condition A (including operating condition A1 and operating condition A2), by Figure 6 As shown in (b), the secondary voltage magnitude parameter is used. Switching cycle parameters And the parameters of the previous secondary side bridge inward shift. Bridge displacement relative parameters Before the update, a secondary side volt-second area contribution analysis was performed to obtain the corresponding first volt-second contribution component sub-models for each operating condition. This process can be represented as: ; here, This represents the volt-second area contribution of the secondary voltage during the first half-cycle after entering the new steady state. For operating condition A, it is a non-power reversal state, i.e. ): Utilizing the central symmetry of the dual active bridge converter, the waveform structure of the new steady state remains consistent with the old steady state without power reversal, only the parameter values ​​change. Therefore, The calculation model formula form and Completely identical, only the updated parameters need to be substituted ( The sign is inverted to reflect the periodic alternation characteristic. This is achieved by utilizing the secondary voltage amplitude parameter. Switching cycle parameters And the updated secondary side bridge inward shift compared to the parameters Bridge displacement relative parameters By performing the updated secondary-side volt-second area contribution analysis, we can obtain the corresponding second volt-second contribution component sub-models for each operating condition A. This process can be represented as: ; It should be noted that, in this calculation process, since the secondary driving pulse remains symmetrical after the update, the sum of the volt-second terms during its transition period is... It can be considered as zero.

[0061] Here, it should be noted that, Indicates the time. Previously, on the secondary side, it was the volt-second area of ​​the last negative half-cycle before the phase shift update; This represents the volt-second area corresponding to the positive half-cycle of the secondary side; This represents the volt-second area corresponding to the negative half-cycle of the secondary side; This represents the volt-second area of ​​the second side during the first positive half-cycle after entering the new steady state.

[0062] For operating condition B (including operating conditions B1 and B2), this is a power reversal, i.e. When power reversal occurs, the inter-bridge shift ratio becomes negative, and the waveform phase relationship is reversed. At this time, the polarity mapping relationship (i.e., ...) is utilized. The negative phase shift angle is mapped to an equivalent positive time interval for integration. The boundary conditions for operating conditions B1 and B2 are also obtained by substituting this polarity mapping relationship into the original condition. The boundary condition is obtained from... Figure 6 As shown in (b), the relevant volt-second area is calculated, and the first volt-second contribution component quantum model is used for operating conditions B1 and B2. And the second volt-second contribution quantum model ,Right now: ; ; Similarly, the sum of the volt-second terms within its transition period It can be considered zero. Therefore, based on the combination of the first volt-second contribution component sub-model and the second volt-second contribution component sub-model corresponding to the above operating conditions, the second volt-second contribution component model for determining the volt-second contribution component of the secondary full-bridge circuit to the energy storage inductor during the transition switching cycle is constructed.

[0063] Furthermore, in the embodiments of this application, based on the principle of zeroing the volt-second area deviation, a volt-second balance analysis is performed according to the aforementioned first volt-second contribution component model and second volt-second contribution component model to determine the volt-second balance compensation model, which is used to solve for the numerical values ​​of the compensation variable parameters in practical applications.

[0064] More specifically, the construction principle of the volt-second balance compensation model is as follows: First, such as Figure 7 As shown, the deviation component of the inductor volt-second area over four consecutive half-cycles involved in the transient process is denoted as... S m ( , , , ), S m The sum of the independent contributions of the original and secondary borders, i.e. . Figure 7 The text marks four key current points, representing the steady-state current points before the transition. I 1. I 2, and the target steady-state current point after the transition. I 3. I 4. To eliminate DC bias, it is essential to ensure a smooth transition of the current from the old steady state to the new steady state. This requires that the volt-second accumulation during the transition process accurately transitions the current from the old steady state to the new steady state. I 1. Transfer to I 3, simultaneously from I 2. Transfer to I 4.

[0065] Specifically, this application achieves this goal by examining two consecutive overlapping integration intervals.

[0066] First interval (corresponding current) I 1 to I 3. Transition): The sum of the volt-second area deviations in this interval is denoted as , its origin , , , composition.

[0067] Second interval (corresponding current)I 2 to I 4. Transition): The sum of the volt-second area deviations of the immediately following overlapping intervals is denoted as , its origin , , Composition. According to the inductor volt-second balance principle, to completely eliminate transient DC bias, the sum of the total deviations in the two intervals must be zero, i.e. Expanding this expression, we get... + + + + + Because the converter immediately enters a new steady state after the transition (i.e., Figure 7 middle( k+1 ) T s (After a certain time), the volt-second area of ​​the adjacent half-cycle in the new steady state and Since they are equal in magnitude but opposite in sign, they cancel each other out. Substituting this condition into the above equation and simplifying, we obtain the volt-second balance compensation model: .

[0068] in, This represents the volt-second area of ​​the last half-cycle before the update time. and This represents the volt-second area over the two half-cycles within the transition switching cycle. This represents the volt-second area of ​​the first half-cycle after entering the new steady state.

[0069] Here, the volt-second balance compensation model is established based on the principle of eliminating the accumulated volt-second bias during the transient process. It aims to reduce the total volt-second area bias within the two consecutive overlapping integration intervals involved in the phase shift update to zero by introducing compensation variables. Specifically, the bias of the first integration interval is defined as... The deviation of the second overlapping interval that follows is To achieve a bias-free transition, the total deviation is required. Since the converter immediately enters a new steady state after the transition, the steady-state component They cancel each other out, while the volt-second components within the transition period... The coefficient 2 is generated because the calculation is repeated in two overlapping intervals. After simplification, the core control model equation can be obtained. .

[0070] Furthermore, by substituting the primary and secondary side volt-second area contributions calculated in the aforementioned first and second volt-second contribution component models into this equilibrium compensation model, the unique compensation variable parameter can be solved. The value is the target compensation amount.

[0071] Furthermore, the calculated target compensation essentially represents an asymmetric correction to the duty cycle of the output voltage waveform of the primary-side full-bridge circuit. To convert this variable into an actual physical drive signal, the control system (such as a DSP or FPGA digital controller) needs to adjust the four switches in the primary-side full-bridge circuit during the transition switching cycle after detecting the phase shift. Q 1. Q 2. Q 3. Q The conduction logic of 4) will be adjusted as follows: Perform positive half-cycle pulse width correction (involving Q 1. Q 4): Based on the existing primary-side phase-shift control signal, the primary-side diagonal switching transistors... Q 1. Q The common conduction time of 4 (i.e., the corresponding primary voltage) Duration of positive level )Increase This can typically be achieved by controlling the pulse width modulator (PWM). Q 1. Turn off or Q 4. The counter comparison value is delayed. This is achieved using the corresponding count value.

[0072] Negative half-cycle pulse width correction (involving Q 2. Q 3) Based on the complementary drive principle of dual active bridges, in order to maintain a constant switching cycle, another set of diagonal switching transistors must be simultaneously activated. Q 2 and Q The common conduction time of 3 (i.e., the corresponding primary voltage) Duration of negative level )reduce .

[0073] like Figure 8 As shown, the general transient DC bias suppression method for DAB converters based on the superposition theorem proposed in this application includes the following practical steps: The phase-shift control loop is used to generate the phase shift within the primary bridge based on the output voltage or power demand. d 1. Compared with the inward shift of the secondary side bridge d 2. Compared with bridge displacement d p To maintain stable output voltage and power.

[0074] A general volt-second area calculation method is used to independently calculate the volt-second area contribution of the primary-side equivalent voltage source and the secondary-side equivalent voltage source based on the input and output voltages and shift ratio parameters of the primary and secondary full-bridge circuits of the converter.

[0075] Transient compensation controller, used to solve for compensation variables based on volt-second balance compensation model. The driving pulse width of the primary-side full-bridge circuit is adjusted to achieve general DC bias suppression in single-phase shift (SPS), extended phase shift (EPS), dual-phase shift (DPS), and triple-phase shift (TPS) modes.

[0076] Continue to refer to Figure 7 This is an overall control flowchart of the suppression method proposed in the embodiments of this application. The specific execution steps of the method include: Step 1: Obtain control parameters. The current phase-shift control signal is obtained in real-time from the converter's closed-loop controller, mainly including the phase shift ratio within the primary bridge. d 1. Compared with the inward shift of the secondary side bridge d 2 and the bridge displacement comparison d p .

[0077] Step two: Calculate the primary side volt-second area contribution. Based on the previously derived controllable volt-second area model and volt-second area deviation model, calculate the compensation variables respectively. Adjustable volt-second area controllable term And the inherent bias term of the volt-second area resulting from the shift ratio parameter update ( ).

[0078] Step 3: Calculate the secondary side volt-second area contribution. First, calculate the secondary side component based on the aforementioned first volt-second contribution component sub-model. Based on whether the converter is in a power reverse flow state and the specific modulation conditions, the secondary-side operating conditions are divided into four categories (i.e., Then, the corresponding component is calculated using the aforementioned second volt-second contribution component sub-model. In this calculation, since the secondary-side driving pulse remains symmetrical after the update, the sum of the volt-second terms during its transition period is... It is considered zero.

[0079] Step four: Solve for and apply the target compensation amount. Summarize the primary and secondary side volt-second area contribution components obtained above and substitute them into a unified volt-second balance compensation model to calculate the required driving compensation variable. d x Ultimately, by adjusting the duty cycle of the primary side bridge arm drive signal through this compensation, the converter inductor current quickly returns to the volt-second balance state within about half a switching cycle, thereby completely eliminating transient DC bias.

[0080] In one specific embodiment of this application, to verify the practicality and correctness of the proposed transient DC bias suppression strategy, a system was built as follows: Figure 2The experimental prototype of the topology shown was subjected to comparative experiments under four typical operating conditions: increasing power flow, decreasing power flow, and reverse power flow. The experimental results are as follows: Figures 9a to 9h As shown.

[0081] In this embodiment, the experimental input is 60V, and the output voltage reference is adjustable within the range of 50-72V, with rated power... P o 500W, switching frequency f s 20kHz, inductor L The primary and secondary filter capacitors are 30µH. C in and C o All are 450µF.

[0082] First, in single-phase shift mode without power reversal, with an input voltage of 60V and an output voltage of 50V, when the inter-bridge phase shift... d p When the value mutates from 0.43 to 0.07, if a traditional direct switching method (such as...) is used... Figure 9a As shown), the inductor current exhibits a significant DC bias, and this bias component requires approximately ten switching cycles to naturally decay to a steady state. However, when the suppression method described in this application is applied (as shown...), the inductor current will exhibit a significant DC bias, and this bias component requires approximately ten switching cycles to decay to a steady state. Figure 9b As shown), the voltage at the midpoint of the primary bridge is adjusted during the first switching cycle after the parameter transition. v ab The pulse width is adjusted to compensate for the volt-second deviation, and the inductor current completes a seamless transition to the new steady state within approximately half a switching cycle, completely eliminating the DC bias. This process conforms to the aforementioned operating condition A1.

[0083] Furthermore, the experiments in this embodiment verify the converter's suppression effect when switching from extended phase-shifted (EPS) modulation to dual phase-shifted (DPS) modulation without power inversion, such as... Figure 9c and Figure 9d As shown. Under the condition of an input voltage of 60V and an output voltage of 50V, the system consists of... d p =0.07 and d Switching from EPS mode with 1=0.1 to d p =0.45, d 1= d 2=0.1DPS mode. This process conforms to the aforementioned operating condition A2.

[0084] Meanwhile, this embodiment experimentally verifies the converter's suppression effect when switching from single-phase-shift (SPS) modulation to extended-phase-shift (EPS) modulation and involving power inversion, such as... Figure 9eand Figure 9f As shown. Under the condition of an input voltage of 60V and an output voltage of 50V, the system consists of... d p Switching to SPS mode with a value of 0.07 d p =-0.03 and d EPS mode with 1=0.05. At this time, the inter-bridge shift ratio changes from positive to negative, and the power flow direction is reversed. This process is consistent with the aforementioned operating condition B1.

[0085] Finally, this embodiment experimentally verifies the converter's suppression effect in three-phase-shift (TPS) modulation mode involving power inversion, such as... Figure 9g and Figure 9h As shown. Under the condition of an input voltage of 60V and an output voltage of 72V, the system consists of... d p =0.05、 d 1 = 0.06 and d Switching from TPS mode with 2=0.02 to d p =-0.07、 d 1 = 0.13 and d The TPS mode is 2=0.08. This complex switching condition conforms to the aforementioned condition B2.

[0086] The prototype results show that the method described in this application has strong versatility. It is not only applicable to various modulation modes such as SPS, EPS, DPS and TPS, but also can achieve rapid suppression of DC bias without additional sensors in various power regulation scenarios, which significantly improves the safety performance and operating efficiency of the converter in dynamic switching scenarios.

[0087] The suppression approach based on the superposition theorem described in this application has high topological universality. It is not only applicable to the single-phase DC-DC dual active bridge converter in the aforementioned embodiments, but can also be extended to AC-DC isolated single-stage converters (such as matrix dual active bridge converters) or three-phase dual active bridge converters. In the AC-DC conversion scenario: its system topology and equivalent voltage source model can still be essentially mapped to... Figure 2 and Figure 3 The only difference from pure DC-DC operation is that... Figure 3 The amplitude of the equivalent voltage source on the AC side varies sinusoidally with the power frequency cycle. Since the converter's switching frequency (e.g., 20kHz in this example) is much higher than the power frequency (50Hz), the amplitude fluctuation of the AC side voltage is minimal during the single transition switching cycle that triggers DC bias suppression, and can be approximated as a constant DC source. Under this quasi-steady-state assumption, the suppression steps for AC-DC operation are as follows: Step 1: Sample the instantaneous voltage on the AC side in real time and use its absolute value as the amplitude parameter of the equivalent voltage source of the corresponding bridge arm; Step two: Using the transient current bias suppression method in the aforementioned embodiments, independently calculate the volt-second contribution of the AC side voltage source during the transition period. Its calculation logic is the same as... Figure 6 The DC operating conditions shown are completely consistent; Step 3: Summarize the volt-second contributions from the AC and DC sides and construct a volt-second balance compensation model to solve for the compensation variables. d x .

[0088] This application is also applicable to three-phase DAB scenarios. Based on the superposition theorem, the three-phase bridge arms can be further decoupled into a linear superposition of multiple independent voltage sources. Simply follow the steps described in this application to calculate the volt-second area deviation of each phase voltage source before and after the phase shift parameter jump, and summarize it into a unified balance equation to solve for the compensation amount. Since its decoupling calculation logic is mathematically consistent with that of the single-phase operating condition, it will not be elaborated further.

[0089] The general transient DC bias suppression device for phase-shift controlled isolated converters provided in this application is described below. The general transient DC bias suppression device for phase-shift controlled isolated converters described below can be referred to in correspondence with the general transient DC bias suppression method for phase-shift controlled isolated converters described above.

[0090] Figure 10 This is a schematic diagram of the structure of the general transient DC bias suppression device for phase-shift controlled isolated converters provided in the embodiments of this application, as shown below. Figure 10 As shown, it includes: The transient compensation calculation module 10 is used to input the monitoring data of the phase shift ratio parameter before and after the update and the primary and secondary voltage parameters into the volt-second balance compensation model when a transient DC bias is caused by an update of the phase shift ratio parameter of the phase-shift controlled isolated converter. The target compensation amount output by the volt-second balance compensation model is obtained. The phase-shift controlled isolated converter includes primary and secondary full-bridge circuits and an energy storage inductor. The transient compensation control module 20 is used to adjust the driving pulse width of the primary-side full-bridge circuit in the subsequent switching cycle using the target compensation amount to eliminate transient DC bias. The volt-second balance compensation model is determined by using the compensation variable parameters corresponding to the introduced target compensation amount to analyze the contribution of the primary and secondary full-bridge circuits to the volt-second area change of the energy storage inductor in the transition switching cycle.

[0091] It is understood that the detailed functional implementation of each of the above units / modules can be found in the description in the aforementioned method embodiments, and will not be repeated here.

[0092] It should be understood that the above-described device is used to execute the methods in the above embodiments. The implementation principle and technical effect of the corresponding program modules in the device are similar to those described in the above methods. The working process of the device can be referred to the corresponding process in the above methods, and will not be repeated here.

[0093] This application provides a general transient DC bias suppression device for phase-shift controlled isolated converters. By utilizing the superposition theorem, the primary and secondary full-bridge circuits of the converter are equivalent to two decoupled independent square wave voltage sources. The inductor volt-second area contribution of each voltage source under arbitrary phase-shift modulation mode and power flow is calculated. During the transition period of phase-shift parameter update or switching, the volt-second balance compensation model is constructed and solved using the introduced primary-side pulse width adjustment variable. This compensates and corrects the duty cycle of the primary-side full-bridge circuit drive signal, which can quickly eliminate transient DC bias and allow the converter to smoothly transition to a new steady state within about half a switching cycle. At the same time, no additional sensors are required, which effectively improves the system's operational stability and efficiency.

[0094] Based on the methods in the above embodiments, this application provides an electronic device, such as... Figure 11 As shown, the electronic device may include a processor 1110, a communications interface 1120, a memory 1130, and a communication bus 1140, wherein the processor 1110, the communications interface 1120, and the memory 1130 communicate with each other via the communication bus 1140. The processor 1110 can call logical instructions in the memory 1130 to execute the methods in the above embodiments.

[0095] Furthermore, the logical instructions in the aforementioned memory 1130 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application.

[0096] Based on the methods in the above embodiments, this application provides a computer-readable storage medium storing a computer program that, when run on a processor, causes the processor to execute the methods in the above embodiments.

[0097] Based on the methods in the above embodiments, this application provides a computer program product that, when run on a processor, causes the processor to execute the methods in the above embodiments.

[0098] It is understood that the processor in the embodiments of this application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor can be a microprocessor or any conventional processor.

[0099] The method steps in this application embodiment can be implemented in hardware or by a processor executing software instructions. The software instructions can consist of corresponding software modules, which can be stored in random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disks, portable hard disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can reside in an ASIC.

[0100] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state disk (SSD)).

[0101] It is understood that the various numerical designations used in the embodiments of this application are merely for the convenience of description and are not intended to limit the scope of the embodiments of this application.

[0102] It should be understood that expressions such as “comprising” and “may include” used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as “comprising” and / or “having” are to be interpreted as indicating a particular characteristic, number, operation, constituent element, component, or combination thereof, but not to exclude the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0103] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A general transient DC bias suppression method for phase-shift controlled isolated converters, characterized in that, include: When a transient DC bias is caused by an update of the phase shift parameter of the phase-shift controlled isolated converter, the monitoring data of the phase shift parameter before and after the update and the primary and secondary voltage parameters are input into the volt-second balance compensation model to obtain the target compensation amount output by the volt-second balance compensation model. The phase-shift controlled isolated converter includes primary and secondary full-bridge circuits and an energy storage inductor; Using the target compensation amount, the driving pulse width of the primary-side full-bridge circuit is adjusted during the subsequent switching cycle to eliminate the transient DC bias. The volt-second balance compensation model is determined by using the compensation variable parameters corresponding to the introduced target compensation amount to analyze the contribution of the primary and secondary full-bridge circuits to the volt-second area change of the energy storage inductor during the transition switching cycle.

2. The general transient DC bias suppression method for phase-shift controlled isolated converters according to claim 1, characterized in that, Before inputting the updated shift ratio parameters and primary / secondary voltage parameters into the volt-second balance compensation model, the method further includes: Based on the original bridge inward shift ratio before and after the update and the compensation variable parameters corresponding to the target compensation amount, the first volt-second contribution component model is determined; the first volt-second contribution component model is used to determine the volt-second contribution component of the primary full-bridge circuit to the energy storage inductor during the transition switching cycle. Based on the power flow state, and the secondary bridge in-bridge shift ratio parameters and inter-bridge shift ratio parameters before and after the update, a second volt-second contribution component model is determined; the second volt-second contribution component model is used to determine the volt-second contribution component generated by the secondary full-bridge circuit to the energy storage inductor during the transition switching cycle; the shift ratio parameters include the primary bridge in-bridge shift ratio parameters, the secondary bridge in-bridge shift ratio parameters, and the inter-bridge shift ratio parameters; Based on the first volt-second contribution component model and the second volt-second contribution component model, a volt-second balance analysis is performed to determine the volt-second balance compensation model.

3. The general transient DC bias suppression method for phase-shift controlled isolated converters according to claim 2, characterized in that, The step of determining the first volt-second contribution component model based on the original side bridge inward displacement comparison parameters before and after the update and the compensation variable parameters corresponding to the target compensation amount includes: Based on the switching cycle parameters, primary voltage amplitude parameters, and the comparison parameters of the primary bridge inward shift before and after the update, the volt-second area deviation term model is determined. Based on the switching cycle parameters, the primary voltage amplitude parameters, and the compensation variable parameters, a volt-second area controllable term model is determined. Based on the volt-second area deviation term model and the volt-second area controllable term model, the first volt-second contribution component model is obtained.

4. The general transient DC bias suppression method for phase-shift controlled isolated converters according to claim 2, characterized in that, The model for determining the second volt-second contribution component based on the power flow direction state and the comparison parameters of the secondary bridge inward and inter-bridge shift before and after the update includes: When the power flow state is in a non-power reversal state or a power reversal state, the corresponding volt-second contribution component quantum model is determined based on the secondary voltage amplitude parameter, the switching cycle parameter, and the secondary bridge inward shift ratio parameter and the bridge inter-shift ratio parameter before and after the update. The second volt-second contribution component model is obtained based on each of the aforementioned volt-second contribution component sub-models.

5. The general transient DC bias suppression method for phase-shift controlled isolated converters according to claim 4, characterized in that, The determination of the volt-second contribution component quantum model under each operating condition based on the secondary voltage amplitude parameter, switching cycle parameter, and the comparison parameters of the secondary bridge inward shift and the bridge-to-bridge shift before and after the update includes: Using the secondary voltage amplitude parameter, the switching cycle parameter, and the previous secondary bridge inward shift ratio parameter and bridge inter-shift ratio parameter, the previous secondary volt-second area contribution analysis was performed to obtain the corresponding first volt-second contribution component quantum model under each operating condition. Using the secondary voltage amplitude parameter, the switching cycle parameter, and the updated secondary bridge inward shift ratio parameter and bridge inter-shift ratio parameter, an updated secondary volt-second area contribution analysis is performed to obtain the corresponding second volt-second contribution component sub-model under each operating condition; the volt-second contribution component sub-model includes the first volt-second contribution component sub-model and the second volt-second contribution component sub-model.

6. The general transient DC bias suppression method for phase-shift controlled isolated converters according to any one of claims 1-5, characterized in that, The phase-shift controlled isolated converter includes, but is not limited to, a single-phase dual active bridge converter, a three-phase dual active bridge converter, a cascaded dual active bridge converter, or an AC-DC isolated converter.

7. A universal transient DC bias suppression device for phase-shift controlled isolated converters, characterized in that, include: The transient compensation calculation module is used to input the monitoring data of the phase shift parameters before and after the update and the primary and secondary voltage parameters into the volt-second balance compensation model when a transient DC bias is caused by an update of the phase shift parameters of the phase-shift control isolated converter. The module then obtains the target compensation amount output by the volt-second balance compensation model. The phase-shift controlled isolated converter includes primary and secondary full-bridge circuits and an energy storage inductor; The transient compensation control module is used to adjust the driving pulse width of the primary-side full-bridge circuit in the subsequent switching cycle using the target compensation amount to eliminate the transient DC bias. The volt-second balance compensation model is determined by using the compensation variable parameters corresponding to the introduced target compensation amount to analyze the contribution of the primary and secondary full-bridge circuits to the volt-second area change of the energy storage inductor in the transition switching cycle.

8. An electronic device, characterized in that, Includes memory and one or more processors; The memory is coupled to the one or more processors, and the memory is used to store computer program code, the computer program code including computer instructions; The one or more processors invoke the computer instructions to cause the electronic device to perform the method as described in any one of claims 1-6.

9. A computer-readable storage medium comprising instructions, characterized in that: When the instructions are executed on an electronic device, the electronic device causes the electronic device to perform the method as described in any one of claims 1-6.

10. A computer program product, comprising a computer program or instructions, characterized in that: When the computer program or instructions are run on an electronic device, the electronic device causes the electronic device to perform the method as described in any one of claims 1-6.

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