Modeling method and device for wide frequency conversion three-phase single-stage AC / DC converter

Abstract

The invention provides a modeling method and device for a wide frequency conversion three-phase single-stage AC / DC converter, and relates to the technical field of converters, and the method comprises the steps: carrying out the modeling of the wide frequency conversion three-phase single-stage AC / DC converter based on a power dynamic balance method, and obtaining a static power balance model; the power dynamic balance method is used for representing that the input power of the wide frequency conversion three-phase single-stage AC / DC converter is equal to the output power; superposing disturbance quantity on static working point parameters in the static power balance model to obtain a small signal model; based on the small signal model, determining a transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter; the transfer function is used for representing the frequency domain response characteristic of the duty ratio disturbance quantity to the output side voltage disturbance quantity so as to optimize a control loop corresponding to the wide frequency conversion three-phase single-stage AC / DC converter. According to the method, the modeling difficulty and complexity of the multi-mode working condition under the DCM can be reduced, and the modeling accuracy, the operation reliability and the stability of the converter are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of converters, and in particular to a modeling method and device for a wide frequency conversion three-phase single-stage AC / DC converter. Background Art

[0002] With the advancement of aircraft electrification, the capacity of aircraft power systems will continue to increase in the future. The frequency of its AC power system will gradually develop from a constant frequency of 400Hz to a wide variable frequency range. It is directly generated by the aircraft's variable-speed AC generator and does not require a constant-speed transmission device or power conversion device. Therefore, compared with the constant-frequency AC power generation system, the variable-frequency AC power generation system has a smaller size and weight and an increased system reliability. Therefore, it is widely used in aircraft AC power generation systems at home and abroad.

[0003] Currently, all three-phase, single-stage, isolated converters in variable-frequency AC power generation systems operate in CCM (Continuous Conduction Mode). However, converters operating in CCM typically employ dual closed-loop control: voltage and current control. Due to the unique characteristics of aviation variable-frequency power supplies, the input power frequency is relatively wide. Therefore, converters operating in CCM require a wide phase-locked loop (PLL) range, placing high demands on the PLL. Furthermore, operating the converter in CCM requires multiple voltage and current sensors, increasing control circuit costs. However, when operating in DCM (Discontinuous Conduction Mode), the converter automatically implements PFC (Power Factor Correction) with a simple control structure, improving converter reliability.

[0004] To rationally design the control loop of a wide-frequency three-phase, single-stage flyback AC / DC (alternating current / direct current) converter, accurate modeling of the converter is necessary. Traditional modeling methods, including state-space averaging, average switching, and unified circuit models, are primarily applicable to converters operating in constant-current (CCM). However, when operating in direct-current (DCM), converters have numerous operating modes. These modeling methods are complex and lack accuracy, making the design of the converter's control loop significantly challenging. Therefore, a modeling method suitable for converters operating in DCM is urgently needed. Summary of the Invention

[0005] The present invention provides a modeling method and device for a wide frequency conversion three-phase single-stage AC / DC converter, which are used to solve the defects in the prior art of a complex modeling process and low accuracy for a converter working in DCM.

[0006] The present invention provides a modeling method for a wide frequency conversion three-phase single-stage AC / DC converter, wherein the wide frequency conversion three-phase single-stage AC / DC converter operates in DCM. The method comprises the following steps.

[0007] The wide frequency conversion three-phase single-stage AC / DC converter is modeled based on a power dynamic balance method to obtain a static power balance model; the power dynamic balance method is used to characterize that the input power of the wide frequency conversion three-phase single-stage AC / DC converter is equal to the output power.

[0008] A disturbance amount is superimposed on the static operating point parameters in the static power balance model to obtain a small signal model.

[0009] Based on the small signal model, a transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter is determined; the transfer function is used to characterize the frequency domain response characteristics of the duty cycle disturbance to the output side voltage disturbance, so as to optimize the control loop corresponding to the wide frequency conversion three-phase single-stage AC / DC converter.

[0010] According to the modeling method of the wide frequency conversion three-phase single-stage AC / DC converter provided by the present invention, the wide frequency conversion three-phase single-stage AC / DC converter is modeled based on the power dynamic balance method to obtain a static power balance model, including: Without considering internal losses, determining the initial input power of the wide frequency conversion three-phase single-stage AC / DC converter as the input power, and constructing the static power balance model based on the input power being equal to the output power; Taking internal losses into consideration, the input power is determined based on a power loss coefficient and an initial input power of the wide frequency conversion three-phase single-stage AC / DC converter; and the static power balance model is constructed based on the input power being equal to the output power.

[0011] According to the modeling method of the wide frequency conversion three-phase single-stage AC / DC converter provided by the present invention, determining the initial input power of the wide frequency conversion three-phase single-stage AC / DC converter includes: The initial input power is determined based on the following formula (1); (1) Among them, P in Indicates the initial input power, V m I represents the input side voltage amplitude of the wide frequency conversion three-phase single-stage AC / DC converter, m represents the input side current amplitude of the wide frequency conversion three-phase single-stage AC / DC converter, D represents the duty cycle, T s Represents the switching period, L l represents the leakage inductance of the three-phase integrated transformer in the wide frequency conversion three-phase single-stage AC / DC converter, Lm represents the primary winding excitation inductance of the three-phase integrated transformer.

[0012] According to the modeling method of the wide frequency conversion three-phase single-stage AC / DC converter provided by the present invention, the static operating point parameters include duty cycle, input side voltage amplitude, input side current amplitude, output side voltage and output side current; The method of superimposing a disturbance on the static operating point parameters in the static power balance model to obtain a small signal model includes: Based on the following formula (2), the disturbance amount is superimposed on the static operating point parameters to obtain target operating parameters; the target operating parameters include a target duty cycle, a target input side voltage amplitude, a target input side current amplitude, a target output side voltage, and a target output side current; (2) in, represents the duty cycle disturbance, Indicates the input side voltage amplitude disturbance, Indicates the input side current amplitude disturbance, Represents the output side voltage disturbance, Indicates the output side current disturbance, V o Indicates the output side voltage, I o represents the output current, d represents the target duty cycle, v m Indicates the target input side voltage amplitude, i m Indicates the target input side current amplitude, v o Indicates the target output side voltage, Indicates the target output side current; The target operating parameters are used to replace the static operating point parameters in the static power balance model to obtain the small signal model.

[0013] According to the modeling method of the wide frequency conversion three-phase single-stage AC / DC converter provided by the present invention, determining the transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter based on the small signal model includes: Ignoring the second-order terms and higher-order AC quantities in the small signal model, the first equation is obtained: Eliminate the DC steady-state components on both sides of the first equation, and In the case of , we get the second equation; The output impedance is determined based on the following formula (3); (3) Where Z represents the output impedance, R represents the output resistance, C represents the output filter capacitor, and s represents a complex variable. Based on the output terminal impedance and the second equation, a transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter is determined.

[0014] According to the modeling method of the wide frequency conversion three-phase single-stage AC / DC converter provided by the present invention, determining the transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter based on the output terminal impedance and the second equation includes: The second equation is updated based on the output terminal impedance to obtain the third equation shown in equation (4); (4) Based on the third equation, the transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter shown in equation (5) is obtained; (5) in, represents the transfer function.

[0015] According to the modeling method of the wide frequency conversion three-phase single-stage AC / DC converter provided by the present invention, the input frequency range of the AC input side of the wide frequency conversion three-phase single-stage AC / DC converter is 360Hz to 800Hz.

[0016] The present invention also provides a modeling device for a wide frequency conversion three-phase single-stage AC / DC converter, comprising the following modules.

[0017] A modeling module is used to model the wide frequency conversion three-phase single-stage AC / DC converter based on a power dynamic balance method to obtain a static power balance model; the power dynamic balance method is used to characterize that the input power of the wide frequency conversion three-phase single-stage AC / DC converter is equal to the output power.

[0018] The disturbance module is used to superimpose a disturbance amount on the static operating point parameters in the static power balance model to obtain a small signal model.

[0019] A determination module is used to determine a transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter based on the small signal model; the transfer function is used to characterize the frequency domain response characteristics of the duty cycle disturbance to the output side voltage disturbance, so as to optimize the control loop corresponding to the wide frequency conversion three-phase single-stage AC / DC converter.

[0020] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the modeling method of the wide frequency conversion three-phase single-stage AC / DC converter as described above is implemented.

[0021] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the modeling method of the wide frequency conversion three-phase single-stage AC / DC converter as described in any one of the above.

[0022] The present invention also provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the computer program implements any of the above-mentioned wide frequency conversion three-phase single-stage AC / DC converter modeling methods.

[0023] The present invention provides a modeling method and device for a wide-frequency three-phase single-stage AC / DC converter. The method models the wide-frequency three-phase single-stage AC / DC converter based on a power dynamic balance method that characterizes input power equal to output power, obtaining a static power balance model. A disturbance is superimposed on the static operating point parameters in the static power balance model to obtain a small-signal model. Based on the small-signal model, a transfer function is determined to characterize the frequency-domain response characteristics of the duty cycle disturbance to the output voltage disturbance, thereby optimizing the control loop corresponding to the wide-frequency three-phase single-stage AC / DC converter. The present invention utilizes the power dynamic balance method to model the converter, significantly reducing the difficulty of modeling multi-modal operation under DCM and improving the converter's modeling accuracy, operational reliability, and stability. Furthermore, after introducing the disturbance into the static operating point parameters, the nonlinear system corresponding to the converter is linearized. When optimizing the control loop based on the transfer function, a single voltage loop control can be used, significantly reducing the complexity and cost of multi-modal operation under DCM. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 The figure is a flow chart of a modeling method for a wide frequency conversion three-phase single-stage AC / DC converter provided by an embodiment of the present invention.

[0026] Figure 2 Schematic diagram of the structure of a wide frequency conversion three-phase single-stage AC / DC converter provided by an embodiment of the present invention.

[0027] Figure 3 It is a Bode diagram of the modeling result corresponding to the transfer function provided by the embodiment of the present invention.

[0028] Figure 4 It is a Bode diagram of the frequency sweep result corresponding to the transfer function provided by the embodiment of the present invention.

[0029] Figure 5 This is the original Bode diagram of the transfer function when no compensation network is added according to the embodiment of the present invention.

[0030] Figure 6 This is a simulated Bode diagram of the transfer function when a compensation network is added according to an embodiment of the present invention.

[0031] Figure 7 1 is a schematic structural diagram of a modeling device for a wide frequency conversion three-phase single-stage AC / DC converter provided by an embodiment of the present invention.

[0032] Figure 8 It is a structural diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0033] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0034] To address the problems in the prior art of complex and low-accuracy modeling of converters operating in discontinuous conduction mode (DCM), an embodiment of the present invention provides a modeling method for a wide-frequency three-phase single-stage AC / DC converter, wherein the wide-frequency three-phase single-stage AC / DC converter operates in discontinuous conduction mode (DCM). Figure 1 FIG. 1 is a flow chart of a modeling method for a wide frequency conversion three-phase single-stage AC / DC converter provided by an embodiment of the present invention. Figure 1 As shown, the method includes the following steps 110 to 130.

[0035] Step 110: Model the wide frequency conversion three-phase single-stage AC / DC converter based on a power dynamic balance method to obtain a static power balance model; the power dynamic balance method is used to characterize that the input power of the wide frequency conversion three-phase single-stage AC / DC converter is equal to the output power.

[0036] It should be noted that the wide frequency conversion three-phase single-stage AC / DC converter adopts a single-stage flyback structure, which is hereinafter referred to as a converter. Figure 2 Schematic diagram of the structure of a wide frequency conversion three-phase single-stage AC / DC converter provided by an embodiment of the present invention. Figure 2As shown in the figure, in actual applications, the input current to the AC input side of the converter is generated by an aircraft variable-speed AC generator. During the converter experiment, a three-phase programmable AC power supply can be used to simulate the aircraft variable-speed AC generator to generate the input current. The frequency of the AC input side of the converter varies widely, and the input frequency range is from 360Hz to 800Hz. The AC input side uses an LC filter to filter out high-frequency harmonic components on the AC input side, and three identical SiC MOSFET power switches S in the power switch module are used to control the AC input side. a 、S b and S c The secondary winding of the three-phase integrated transformer is connected to a rectifier bridge composed of diodes D1 to D6, and the DC filter capacitor C is used to filter the voltage ripple on the DC output side, thereby providing a stable DC output voltage for the DC power equipment in the load. The three-phase AC element voltages on the AC input side of the transformer are: ,in, represents the angular frequency of the three-phase AC power supply, and V represents the effective value of the AC input voltage of the converter. Furthermore, in this converter, the three-phase integrated transformer adopts a three-phase five-column structure. The primary winding of the three-phase integrated transformer adopts a Y-type connection, and the secondary winding adopts a Y-type or Δ-type connection. This reduces the internal circulating current of the transformer and prevents saturation of the three-phase integrated transformer's core.

[0037] Discontinuous conduction mode (DCM) refers to a mode in which the inductor current drops to zero before the end of a switching cycle. Discontinuous conduction mode includes four operating modes: charging mode, first discharge mode, second discharge mode, and discontinuous mode. Due to the large number of operating modes in DCM, using modeling methods suitable for CCM, such as state-space averaging, average switching, and a unified circuit model, can be complex and inaccurate, leading to greater difficulty in designing the control loop within the converter. Therefore, in an embodiment of the present invention, a dynamic power balance method is employed. Specifically, based on the energy conservation principle that the input power equals the output power of the converter, the converter is modeled to obtain a static power balance model. This avoids the complexity of detailed analysis of each operating mode in DCM during the modeling process, reduces the difficulty of modeling the entire converter under multi-modal operation, and improves the accuracy of converter modeling.

[0038] Step 120: Superimpose a disturbance on the static operating point parameters in the static power balance model to obtain a small signal model.

[0039] Specifically, the converter is a nonlinear system. Switching within the converter causes the energy it transmits to shift between different circuits, making direct analysis of the dynamic characteristics of the entire system complex. Therefore, in this embodiment of the present invention, after constructing a static power balance model, a disturbance signal is introduced at the converter's static operating point parameters to generate a small-signal model. This linearizes the nonlinear system and simplifies subsequent analysis.

[0040] It should be noted that the static operating point parameters are a set of electrical state parameters of the converter during steady-state operation, and the static operating point parameters include duty cycle, input side voltage amplitude, input side current amplitude, output side voltage and output side current.

[0041] Step 130: Determine a transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter based on the small signal model; the transfer function is used to characterize the frequency domain response characteristics of the duty cycle disturbance to the output side voltage disturbance, so as to optimize the control loop corresponding to the wide frequency conversion three-phase single-stage AC / DC converter.

[0042] Specifically, after determining the small-signal model, the converter's transfer function is determined based on the small-signal model. This facilitates frequency-domain analysis and stability assessment of the converter based on the transfer function, thereby accurately designing the converter's control loop. For example, a compensation network is precisely designed based on the transfer function to perform loop compensation, ensuring that the converter's control bandwidth and stability margin meet design requirements, thereby improving the stability and dynamics of the converter's control system. Furthermore, the transfer function characterizes the frequency-domain response characteristics of the duty cycle disturbance to the output voltage disturbance. Because the power dynamic balance method is used for modeling, a single voltage-loop control scheme can be employed when designing the converter's control loop. Specifically, only the output voltage disturbance needs to be considered, and power balance can be maintained by adjusting the duty cycle. Compared to the prior art dual closed-loop voltage and current control strategy operating in CCM, this significantly reduces complexity and cost, thereby improving the converter's power density and reliability.

[0043] It should be noted that in the embodiments of the present invention, a limiting device is added to the converter's control loop to ensure that the converter operates in DCM. From the perspective of the converter's input characteristics, the converter behaves as a purely resistive load, enabling the converter to automatically implement PFC (Power Factor Correction) functionality, simplifying the converter's control structure and improving its reliability. The converter in the embodiments of the present invention can be a Buck-Boost AC / DC converter operating in DCM, capable of both boost and buck functions, achieving unity power factor simply by operating the controller in DCM. The converter has a simple structure, and the DC output voltage can be adjusted over a wide range. Furthermore, the Buck-Boost AC / DC converter is relatively easy to achieve electrical isolation, and its input current has low harmonic content, making it an ideal AC / DC converter.

[0044] A modeling method for a wide-frequency three-phase single-stage AC / DC converter provided in an embodiment of the present invention models the wide-frequency three-phase single-stage AC / DC converter based on a power dynamic balance method that characterizes input power equal to output power, obtaining a static power balance model. A disturbance is superimposed on the static operating point parameters in the static power balance model to obtain a small-signal model. Based on the small-signal model, a transfer function is determined to characterize the frequency-domain response characteristics of the duty cycle disturbance to the output voltage disturbance, thereby optimizing the control loop corresponding to the wide-frequency three-phase single-stage AC / DC converter. In an embodiment of the present invention, the power dynamic balance method is used to model the converter, significantly reducing the difficulty of modeling multi-modal operation under DCM and improving the converter's modeling accuracy, operational reliability, and stability. Furthermore, after introducing the disturbance into the static operating point parameters, the nonlinear system corresponding to the converter is linearized. When optimizing the control loop based on the transfer function, a single voltage loop control can be used, significantly reducing the complexity and cost of multi-modal operation under DCM.

[0045] Furthermore, the wide frequency conversion three-phase single-stage AC / DC converter is modeled based on the power dynamic balance method to obtain a static power balance model, including: Without considering internal losses, determining the initial input power of the wide frequency conversion three-phase single-stage AC / DC converter as the input power, and constructing the static power balance model based on the input power being equal to the output power; Taking internal losses into consideration, the input power is determined based on a power loss coefficient and an initial input power of the wide frequency conversion three-phase single-stage AC / DC converter; and the static power balance model is constructed based on the input power being equal to the output power.

[0046] Specifically, in embodiments of the present invention, the case where internal converter losses are not considered is typically used for theoretical analysis under ideal conditions. The initial input power is directly determined as the input power, and a static power balance model is constructed based on the principle that input power equals output power. However, the case where internal converter losses are considered is closer to practical applications. In practical applications, the converter will have conduction losses, switching losses, and core losses. In this case, the power loss coefficient can be determined based on the internal converter conduction losses, switching losses, and core losses, as well as historical experience. The product of the power loss coefficient and the initial input power is calculated, and this product is the input power. Subsequently, the static power balance model can be constructed using the principle that input power equals output power.

[0047] Furthermore, determining the initial input power of the wide frequency conversion three-phase single-stage AC / DC converter includes: The initial input power is determined based on the following formula (1); (1) Among them, P in Indicates the initial input power, V m I represents the input side voltage amplitude of the wide frequency conversion three-phase single-stage AC / DC converter, m represents the input side current amplitude of the wide frequency conversion three-phase single-stage AC / DC converter, D represents the duty cycle, T s Represents the switching period, L l represents the leakage inductance of the three-phase integrated transformer in the wide frequency conversion three-phase single-stage AC / DC converter, L m represents the primary winding excitation inductance of the three-phase integrated transformer, and m=[a, b, c].

[0048] The output power of the converter is P o =V o I o , where P o Indicates output power, V o Indicates the output side voltage, I o Indicates the output current.

[0049] Taking the ideal case as an example, based on the input power being equal to the output power, the static power balance model constructed is shown in Equation (6).

[0050] (6) Furthermore, the static operating point parameters in the static power balance model are superimposed with a disturbance value to obtain a small signal model, including: Based on the following formula (2), the disturbance amount is superimposed on the static operating point parameters to obtain target operating parameters; the target operating parameters include a target duty cycle, a target input side voltage amplitude, a target input side current amplitude, a target output side voltage, and a target output side current; (2) in, represents the duty cycle disturbance, Indicates the input side voltage amplitude disturbance, Indicates the input side current amplitude disturbance, Represents the output side voltage disturbance, Indicates the output side current disturbance, V o Indicates the output side voltage, I o represents the output current, d represents the target duty cycle, v m Indicates the target input side voltage amplitude, i m Indicates the target input side current amplitude, v o Indicates the target output side voltage, Indicates the target output side current; The target operating parameters are used to replace the static operating point parameters in the static power balance model to obtain the small signal model.

[0051] Specifically, after obtaining the target operating parameters shown in formula (2), the target operating parameters are substituted into formula (6) to obtain the small signal model shown in formula (7).

[0052] (7) Furthermore, determining the transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter based on the small signal model includes: Ignoring the second-order terms and higher-order AC quantities in the small signal model, the first equation is obtained: Eliminate the DC steady-state components on both sides of the first equation, and In the case of , we get the second equation; The output impedance is determined based on the following formula (3); (3) Where Z represents the output impedance, R represents the output resistance, C represents the output filter capacitor, and s represents a complex variable. Based on the output terminal impedance and the second equation, a transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter is determined.

[0053] Specifically, after determining the small signal model, since the disturbance signal introduced by the static operating point parameters is small enough, the second-order terms and high-order AC quantities in the small signal model can be ignored relative to the first-order terms. Therefore, after ignoring the second-order terms and high-order AC quantities in Equation (7), the first equation shown in Equation (8) can be obtained by sorting.

[0054] (8) Since the converter is in steady state at the static operating point parameters, the DC steady-state components are already balanced in the steady state. Therefore, after the disturbance signal is introduced, the equation for the disturbance part should only contain the relationship between the disturbance variables. Therefore, after obtaining the first equation, the DC steady-state components on both sides of the first equation are eliminated to obtain the second equation. This second equation only describes the correlation between the disturbance variables, making subsequent analysis more indirect and able to independently study the small signal response without being affected by the static operating point parameters. This second equation is shown in Equation (9).

[0055] (9) Then, the second equation is updated according to the input impedance to determine the transfer function.

[0056] Furthermore, determining the transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter based on the output terminal impedance and the second equation includes: The second equation is updated based on the output terminal impedance to obtain the third equation shown in equation (4); (4) Based on the third equation, the transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter shown in equation (5) is obtained; (5) in, represents the transfer function.

[0057] Specifically, after substituting Equation (3) into Equation (9), the third equation shown in Equation (4) can be obtained. After converting the third equation, the ratio of the output side voltage disturbance to the duty cycle disturbance is calculated, and the initial derivation formula of the transfer function shown in Equation (10) can be determined.

[0058] (10) Substituting the known quantities into equation (10) and simplifying it, we can obtain the intermediate derivation formula of the transfer function shown in equation (11).

[0059] (11) After simplifying Equation (11), we can obtain the transfer function shown in Equation (5).

[0060] After determining the transfer function, in order to verify the accuracy of the model built in the embodiment of the present invention, the theoretical modeling result Bode diagram corresponding to the transfer function is drawn, and the actual frequency sweep result Bode diagram is obtained by frequency sweeping using simulation software. Figure 3 is the Bode diagram of the modeling result corresponding to the transfer function provided by the embodiment of the present invention, Figure 4 is the Bode diagram of the sweep frequency result corresponding to the transfer function provided in the embodiment of the present invention, such as Figure 3 and Figure 4 As shown, due to the high frequency interval (i.e. [10 4 Hz, 10 5 Hz]), the amplitude-frequency curves of the modeled Bode plot and the swept-frequency Bode plot do not completely overlap in the high-frequency range. However, in the low-frequency range, the amplitude-frequency curves of the modeled Bode plot and the swept-frequency Bode plot completely overlap. In this embodiment of the present invention, by ignoring the second-order terms and higher-order AC quantities in the small-signal model, the low-frequency range is completely overlapped, verifying the accuracy of the constructed model.

[0061] In addition, when no compensation network is designed in the control loop, the original Bode diagram of the transfer function is as follows: Figure 5 After using the transfer function to design the compensation network, the simulation software is used to draw the Figure 6 The simulation Bode diagram shown in Figure 3 is used to analyze the stability and dynamic characteristics of the converter control system. Figure 5 From the amplitude-frequency curve in the figure, we can see that the phase margin is about 130° when the compensation network is not added, but the amplitude decreases slightly. Figure 6 From the amplitude-frequency curve in , we can see that the phase margin is about 75° after adding the compensation network, but the amplitude decreases significantly. The control bandwidth and stability margin of the converter both meet the stability requirements of the converter.

[0062] The modeling device of the wide frequency conversion three-phase single-stage AC / DC converter provided by the present invention is described below. The modeling device of the wide frequency conversion three-phase single-stage AC / DC converter described below and the modeling method of the wide frequency conversion three-phase single-stage AC / DC converter described above can be referred to each other.

[0063] The embodiment of the present invention also provides a modeling device for a wide frequency conversion three-phase single-stage AC / DC converter. Figure 7 Schematic diagram of the structure of the modeling device of the wide frequency conversion three-phase single-stage AC / DC converter provided by the embodiment of the present invention. Figure 7 As shown, the modeling device 700 of the wide frequency conversion three-phase single-stage AC / DC converter includes: a modeling module 710 , a disturbance module 720 and a determination module 730 .

[0064] The modeling module 710 is used to model the wide frequency conversion three-phase single-stage AC / DC converter based on the power dynamic balance method to obtain a static power balance model; the power dynamic balance method is used to characterize that the input power of the wide frequency conversion three-phase single-stage AC / DC converter is equal to the output power.

[0065] The disturbance module 720 is configured to superimpose a disturbance on the static operating point parameters in the static power balance model to obtain a small signal model.

[0066] A determination module 730 is configured to determine a transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter based on the small signal model; the transfer function is configured to characterize the frequency domain response characteristics of the duty cycle disturbance to the output side voltage disturbance, so as to optimize the control loop corresponding to the wide frequency conversion three-phase single-stage AC / DC converter.

[0067] A modeling device for a wide-frequency three-phase single-stage AC / DC converter provided in an embodiment of the present invention models the wide-frequency three-phase single-stage AC / DC converter based on a power dynamic balance method that characterizes input power equal to output power, obtaining a static power balance model. A disturbance is superimposed on the static operating point parameters in the static power balance model to obtain a small-signal model. Based on the small-signal model, a transfer function is determined to characterize the frequency-domain response characteristics of the duty cycle disturbance to the output voltage disturbance, thereby optimizing the control loop corresponding to the wide-frequency three-phase single-stage AC / DC converter. In this embodiment of the present invention, the power dynamic balance method is used to model the converter, significantly reducing the difficulty of modeling multi-modal operation under DCM and improving the modeling accuracy, operational reliability, and stability of the converter. Furthermore, after introducing the disturbance into the static operating point parameters, the nonlinear system corresponding to the converter is linearized. When optimizing the control loop based on the transfer function, a single voltage loop control can be used, significantly reducing the complexity and cost of multi-modal operation under DCM.

[0068] Optionally, the modeling module 710 is specifically configured to: Without considering internal losses, determining the initial input power of the wide frequency conversion three-phase single-stage AC / DC converter as the input power, and constructing the static power balance model based on the input power being equal to the output power; Taking internal losses into consideration, the input power is determined based on a power loss coefficient and an initial input power of the wide frequency conversion three-phase single-stage AC / DC converter; and the static power balance model is constructed based on the input power being equal to the output power.

[0069] Optionally, the modeling module 710 is specifically configured to: The initial input power is determined based on the following formula (1); (1) Among them, P in Indicates the initial input power, V m I represents the input side voltage amplitude of the wide frequency conversion three-phase single-stage AC / DC converter, m represents the input side current amplitude of the wide frequency conversion three-phase single-stage AC / DC converter, D represents the duty cycle, T s Represents the switching period, L l represents the leakage inductance of the three-phase integrated transformer in the wide frequency conversion three-phase single-stage AC / DC converter, L m represents the primary winding excitation inductance of the three-phase integrated transformer.

[0070] Optionally, the static operating point parameters include duty cycle, input side voltage amplitude, input side current amplitude, output side voltage and output side current.

[0071] Optionally, the disturbance module 720 is specifically configured to: Based on the following formula (2), the disturbance amount is superimposed on the static operating point parameters to obtain target operating parameters; the target operating parameters include a target duty cycle, a target input side voltage amplitude, a target input side current amplitude, a target output side voltage, and a target output side current; (2) in, represents the duty cycle disturbance, Indicates the input side voltage amplitude disturbance, Indicates the input side current amplitude disturbance, Represents the output side voltage disturbance, Indicates the output side current disturbance, V o Indicates the output side voltage, I o represents the output current, d represents the target duty cycle, v m Indicates the target input side voltage amplitude, i m Indicates the target input side current amplitude, v o Indicates the target output side voltage, Indicates the target output side current; The target operating parameters are used to replace the static operating point parameters in the static power balance model to obtain the small signal model.

[0072] Optionally, the determination module 730 is specifically configured to: Ignoring the second-order terms and higher-order AC quantities in the small signal model, the first equation is obtained: Eliminate the DC steady-state components on both sides of the first equation, and In the case of , we get the second equation; The output impedance is determined based on the following formula (3); (3) Where Z represents the output impedance, R represents the output resistance, C represents the output filter capacitor, and s represents a complex variable. Based on the output terminal impedance and the second equation, a transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter is determined.

[0073] Optionally, the determination module 730 is specifically configured to: The second equation is updated based on the output terminal impedance to obtain the third equation shown in equation (4); (4) Based on the third equation, the transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter shown in equation (5) is obtained; (5) in, represents the transfer function.

[0074] Optionally, the input frequency range of the AC input side of the wide frequency conversion three-phase single-stage AC / DC converter is 360 Hz to 800 Hz.

[0075] Figure 8 Schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. Figure 8 As shown, the electronic device may include: a processor 810, a communication interface 820, a memory 830, and a communication bus 840, wherein the processor 810, the communication interface 820, and the memory 830 communicate with each other via the communication bus 840. The processor 810 may call the logic instructions in the memory 830 to execute the modeling method of the wide frequency conversion three-phase single-stage AC / DC converter, which includes: The wide frequency conversion three-phase single-stage AC / DC converter is modeled based on a power dynamic balance method to obtain a static power balance model; the power dynamic balance method is used to characterize that the input power of the wide frequency conversion three-phase single-stage AC / DC converter is equal to the output power; Superimposing a disturbance on the static operating point parameters in the static power balance model to obtain a small signal model; Based on the small signal model, a transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter is determined; the transfer function is used to characterize the frequency domain response characteristics of the duty cycle disturbance to the output side voltage disturbance, so as to optimize the control loop corresponding to the wide frequency conversion three-phase single-stage AC / DC converter.

[0076] Furthermore, the logic instructions in the aforementioned memory 830 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 the present invention, or the portion 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, stored in a storage medium, includes instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, mobile hard drives, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical disks.

[0077] On the other hand, the present invention further provides a computer program product, comprising a computer program. The computer program may be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can perform the modeling method of the wide frequency conversion three-phase single-stage AC / DC converter provided by the above methods, the method comprising: The wide frequency conversion three-phase single-stage AC / DC converter is modeled based on a power dynamic balance method to obtain a static power balance model; the power dynamic balance method is used to characterize that the input power of the wide frequency conversion three-phase single-stage AC / DC converter is equal to the output power; Superimposing a disturbance on the static operating point parameters in the static power balance model to obtain a small signal model; Based on the small signal model, a transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter is determined; the transfer function is used to characterize the frequency domain response characteristics of the duty cycle disturbance to the output side voltage disturbance, so as to optimize the control loop corresponding to the wide frequency conversion three-phase single-stage AC / DC converter.

[0078] In another aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for modeling a wide frequency conversion three-phase single-stage AC / DC converter provided by the above methods is implemented. The method includes: The wide frequency conversion three-phase single-stage AC / DC converter is modeled based on a power dynamic balance method to obtain a static power balance model; the power dynamic balance method is used to characterize that the input power of the wide frequency conversion three-phase single-stage AC / DC converter is equal to the output power; Superimposing a disturbance on the static operating point parameters in the static power balance model to obtain a small signal model; Based on the small signal model, a transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter is determined; the transfer function is used to characterize the frequency domain response characteristics of the duty cycle disturbance to the output side voltage disturbance, so as to optimize the control loop corresponding to the wide frequency conversion three-phase single-stage AC / DC converter.

[0079] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0080] Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a necessary general-purpose hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods described in each embodiment or certain portions of the embodiments.

[0081] Finally, 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A modeling method for a wide frequency three-phase single-stage AC / DC converter, characterized in that: The wide frequency conversion three-phase single-stage AC / DC converter operates in DCM, and the method includes: The wide frequency conversion three-phase single-stage AC / DC converter is modeled based on a power dynamic balance method to obtain a static power balance model; the power dynamic balance method is used to characterize that the input power of the wide frequency conversion three-phase single-stage AC / DC converter is equal to the output power; Superimposing a disturbance on the static operating point parameters in the static power balance model to obtain a small signal model; Based on the small signal model, a transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter is determined; the transfer function is used to characterize the frequency domain response characteristics of the duty cycle disturbance to the output side voltage disturbance, so as to optimize the control loop corresponding to the wide frequency conversion three-phase single-stage AC / DC converter.

2. The modeling method of a wide frequency conversion three-phase single-stage AC / DC converter according to claim 1, characterized in that: The wide frequency conversion three-phase single-stage AC / DC converter is modeled based on the power dynamic balance method to obtain a static power balance model, including: Without considering internal losses, determining the initial input power of the wide frequency conversion three-phase single-stage AC / DC converter as the input power, and constructing the static power balance model based on the input power being equal to the output power; Taking internal losses into consideration, the input power is determined based on a power loss coefficient and an initial input power of the wide frequency conversion three-phase single-stage AC / DC converter; and the static power balance model is constructed based on the input power being equal to the output power.

3. The modeling method of a wide frequency conversion three-phase single-stage AC / DC converter according to claim 2, characterized in that: Determining the initial input power of the wide frequency conversion three-phase single-stage AC / DC converter includes: The initial input power is determined based on the following formula (1); （1） Among them, P in Indicates the initial input power, V m I represents the input side voltage amplitude of the wide frequency conversion three-phase single-stage AC / DC converter, m represents the input side current amplitude of the wide frequency conversion three-phase single-stage AC / DC converter, D represents the duty cycle, T s Represents the switching period, L l represents the leakage inductance of the three-phase integrated transformer in the wide frequency conversion three-phase single-stage AC / DC converter, L m represents the primary winding excitation inductance of the three-phase integrated transformer.

4. The modeling method of a wide frequency conversion three-phase single-stage AC / DC converter according to claim 1, characterized in that: The static operating point parameters include duty cycle, input side voltage amplitude, input side current amplitude, output side voltage and output side current; The method of superimposing a disturbance on the static operating point parameters in the static power balance model to obtain a small signal model includes: Based on the following formula (2), the disturbance amount is superimposed on the static operating point parameters to obtain target operating parameters; the target operating parameters include a target duty cycle, a target input side voltage amplitude, a target input side current amplitude, a target output side voltage, and a target output side current; （2） in, represents the duty cycle disturbance, Indicates the input side voltage amplitude disturbance, Indicates the input side current amplitude disturbance, Represents the output side voltage disturbance, Indicates the output side current disturbance, V o Indicates the output side voltage, I o represents the output current, d represents the target duty cycle, v m Indicates the target input side voltage amplitude, i m Indicates the target input side current amplitude, v o Indicates the target output side voltage, Indicates the target output side current; The target operating parameters are used to replace the static operating point parameters in the static power balance model to obtain the small signal model.

5. The modeling method of a wide frequency conversion three-phase single-stage AC / DC converter according to claim 1, characterized in that: The determining, based on the small signal model, a transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter includes: Ignoring the second-order terms and higher-order AC quantities in the small signal model, the first equation is obtained: Eliminate the DC steady-state components on both sides of the first equation, and In the case of , we get the second equation; The output impedance is determined based on the following formula (3); （3） Where Z represents the output impedance, R represents the output resistance, C represents the output filter capacitor, and s represents a complex variable. Based on the output terminal impedance and the second equation, a transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter is determined.

6. The modeling method of a wide frequency conversion three-phase single-stage AC / DC converter according to claim 5, characterized in that: The step of determining a transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter based on the output terminal impedance and the second equation includes: The second equation is updated based on the output terminal impedance to obtain the third equation shown in equation (4); （4） Based on the third equation, the transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter shown in equation (5) is obtained; （5） in, represents the transfer function.

7. The modeling method of a wide frequency conversion three-phase single-stage AC / DC converter according to claim 1, characterized in that: The input frequency range of the AC input side of the wide frequency conversion three-phase single-stage AC / DC converter is 360 Hz to 800 Hz.

8. A modeling device for a wide frequency three-phase single-stage AC / DC converter, characterized in that: include: a modeling module for modeling the wide frequency conversion three-phase single-stage AC / DC converter based on a power dynamic balance method to obtain a static power balance model; the power dynamic balance method is used to characterize that the input power of the wide frequency conversion three-phase single-stage AC / DC converter is equal to the output power; A disturbance module, configured to superimpose a disturbance on the static operating point parameters in the static power balance model to obtain a small signal model; A determination module is used to determine a transfer function corresponding to the wide frequency conversion three-phase single-stage AC / DC converter based on the small signal model; the transfer function is used to characterize the frequency domain response characteristics of the duty cycle disturbance to the output side voltage disturbance, so as to optimize the control loop corresponding to the wide frequency conversion three-phase single-stage AC / DC converter.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the modeling method of the wide frequency conversion three-phase single-stage AC / DC converter according to any one of claims 1 to 7 is implemented.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the modeling method of the wide frequency conversion three-phase single-stage AC / DC converter according to any one of claims 1 to 7 is implemented.

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