Load current feedforward control method and system for hybrid modular direct-current transformer

Abstract

The invention provides a load current feedforward control method and system for a hybrid modular direct-current transformer, and relates to the technical field of direct-current transformer dynamic performance improvement control, and the method specifically comprises the steps: obtaining a corresponding HMDCT voltage and current measured value according to a selected control mode; the difference value between the voltage measured value and the expected value is input into a P I controller, and the error compensation amount is obtained; constructing a transfer function of a load current feed-forward path in real time; based on a current measured value, an error compensation amount and a transfer function of a load current feed-forward path, an improved feed-forward control law is constructed, and an expected value of PS-DAB output current is calculated in real time; according to the expected value of the output current of the PS-DAB, the optimal phase shift ratio of the PS-DAB is calculated, and PWM waves are generated through modulation and used for controlling the HMDCT in the mode; according to the invention, the change of load current or power can be quickly responded, and excellent output voltage stability and dynamic performance can be maintained even when the tidal current direction changes suddenly.

Description

Technical Field

[0001] The present disclosure relates to the technical field of dynamic performance improvement control of direct current transformers, and in particular to a load current feedforward control method and system for a hybrid modular direct current transformer. Background Art

[0002] With the rapid growth of various types of renewable energy, loads and energy storage, DC transformers have become the key hub and core equipment in DC distribution systems, undertaking important functions such as bidirectional power conversion, transmission and electrical isolation between ports and DC busbars. Their performance is directly related to the system operation efficiency and the utilization rate of renewable energy.

[0003] In recent years, in order to further improve the performance of DC transformers, some scholars have proposed the concept of "Hybrid modular DC transformer (HMDCT)", which has attracted widespread attention from academia and industry, and a series of similar variants have been derived on this basis. Compared with the traditional input series output parallel (ISOP) DC transformer composed only of phase-shift dual active bridge (PS-DAB) converter submodule (hereinafter referred to as PS-DAB), HMDCT uses series resonant dual active bridge (SR-DAB) converter submodule (hereinafter referred to as SR-DAB) to replace part of the PS-DAB in the traditional DC transformer, which not only significantly improves the overall conversion efficiency of the DC transformer, but also retains the voltage / current flexible controllable advantage brought by PS-DAB to the traditional DC transformer.

[0004] Although HMDCT has significant advantages in steady-state performance such as efficiency and controllability, its dynamic performance is not as good as that of a DC transformer composed only of PS-DAB. The reason is that SR-DAB operates in series resonant mode and dominates the total transmission power of HMDCT, causing HMDCT to exhibit slow dynamic characteristics similar to SR-DAB. When the output side is connected to a pulsating power load or power supply, the slow dynamic characteristics mean larger ripple and overshoot, which may cause interference to other equipment or force the system to require a larger capacity filter capacitor, thereby increasing costs and shortening system life. The above problems seriously limit the further replacement of HMDCT for traditional DC transformers in fields such as microgrids, renewable energy generation, and DC traction, and also restrict the improvement of DC transformer performance in these fields. Therefore, the dynamic performance of HMDCT is in urgent need of improvement. Summary of the invention

[0005] In order to solve the above problems, the present disclosure proposes a hybrid modular DC transformer load current feedforward control method and system, which can improve the dynamic performance of HMDCT, quickly respond to changes in load current or power, and maintain excellent output voltage stability even when the power flow direction changes suddenly.

[0006] According to some embodiments, the present disclosure adopts the following technical solutions:

[0007] A hybrid modular DC transformer load current feedforward control method is provided for a hybrid modular DC transformer HMDCT including at least one PS-DAB and one SR-DAB, which quickly responds to changes in load current. The specific control steps are as follows:

[0008] According to the selected control mode, the corresponding HMDCT voltage and current measured values ​​are obtained;

[0009] The difference between the measured voltage value and its expected value is taken as the control error and input into the PI controller to obtain the error compensation amount;

[0010] According to the hardware parameters of HMDCT and the measured voltage value, the transfer function of the load current feedforward path is constructed in real time;

[0011] Based on the measured current value, error compensation amount and the transfer function of the load current feedforward path, an improved feedforward control law is constructed to calculate the expected value of the PS-DAB output current in real time;

[0012] According to the expected value of the PS-DAB output current, the optimal shift phase of the PS-DAB is calculated, and the PWM wave is modulated to generate a PWM wave for controlling the HMDCT in the above mode.

[0013] According to some embodiments, the present disclosure adopts the following technical solutions:

[0014] A hybrid modular DC transformer load current feedforward control system, for a hybrid modular DC transformer HMDCT including at least one PS-DAB and one SR-DAB, quickly responds to changes in load current, comprising:

[0015] The data real-time acquisition module is configured to: obtain the corresponding HMDCT voltage and current measured values ​​according to the selected control mode;

[0016] The error compensation calculation module is configured to: take the difference between the actual voltage value and the expected value as the control error, input it into the PI controller, and obtain the error compensation amount;

[0017] The transfer function building module is configured to: build the transfer function of the load current feedforward path in real time according to the hardware parameters of the HMDCT and the measured voltage value;

[0018] The current expectation calculation module is configured to: based on the measured current value, the error compensation amount, and the transfer function of the load current feedforward path, construct an improved feedforward control law, and calculate the expected value of the output current of the PS-DAB in real time;

[0019] The PWM wave generation module is configured to: according to the expected value of the output current of the PS-DAB, calculate the optimal phase shift ratio of the PS-DAB, modulate and generate a PWM wave for controlling the HMDCT in the said mode.

[0020] According to some embodiments, the present disclosure adopts the following technical solutions:

[0021] A computer program product includes a computer program, and when the computer program is executed by a processor, it implements the described method for feedforward control of the load current of a hybrid modular DC transformer.

[0022] According to some embodiments, the present disclosure adopts the following technical solutions:

[0023] A non-transitory computer-readable storage medium is used to store computer instructions, and when the computer instructions are executed by a processor, they implement the described method for feedforward control of the load current of a hybrid modular DC transformer.

[0024] According to some embodiments, the present disclosure adopts the following technical solutions:

[0025] An electronic device includes: a processor, a memory, and a computer program; wherein, the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device runs, the processor executes the computer program stored in the memory so that the electronic device executes and implements the described method for feedforward control of the load current of a hybrid modular DC transformer.

[0026] Compared with the prior art, the beneficial effects of the present disclosure are as follows:

[0027] The present disclosure designs a reasonable improved load current feedforward method, establishes a linear "control input-output voltage" equivalent control loop, can approximately eliminate the influence of load current disturbance on the control loop, can make the output voltage quickly recover to the steady-state value within several switching cycles after the load step, and can also naturally adapt to the change of the power flow direction. By slightly adjusting the control parameters, this method can flexibly switch from the low-voltage side voltage control mode of the HMDCT to the high-voltage side voltage control mode. In addition, the present disclosure does not require a complex virtual state quantity peak measurement and estimation circuit, nor a complex state observer, and can be realized only by adding a second-order filter (i.e., the transfer function of the load current feedforward path) on the basis of traditional PI control, with the characteristics of simple structure, less calculation amount, and strong engineering practicability. Description of the Drawings

[0028] The accompanying drawings constituting a part of the present disclosure are used to provide a further understanding of the present disclosure. The illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation on the present disclosure.

[0029] Figure 1 This is an implementation flow chart corresponding to the two control modes of the HMDCT low-voltage side voltage and high-voltage side voltage in Example 1.

[0030] Figure 2 This is a schematic diagram of the HMDCT topology of Example 1.

[0031] Figure 3 It is an implementation block diagram and equivalent principle schematic diagram of the HMDCT low-voltage side voltage control mode in Example 1.

[0032] Figure 4 It is an implementation block diagram and equivalent principle schematic diagram of the HMDCT high-voltage side voltage control mode in Example 1.

[0033] Figure 5 This is a comparison diagram of the simulation waveforms under the HMDCT low-voltage side output voltage control mode in Example 1 with the traditional "PI only" and "PI+load current feedforward" methods.

[0034] Figure 6 This is a comparison diagram of the simulation waveforms of the traditional "PI only" and "PI+load current feedforward" methods when the load current (power flow) direction is reversed in the HMDCT low-voltage side output voltage control mode in Example 1.

[0035] Figure 7 This is a comparison diagram of the simulation waveforms under the HMDCT high-voltage side output voltage control mode in Example 1 with the traditional "PI only" and "PI+load current feedforward" methods. DETAILED DESCRIPTION

[0036] The present disclosure is further described below in conjunction with the accompanying drawings and embodiments.

[0037] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present disclosure. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present disclosure belongs.

[0038] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0039] Example 1

[0040] In one embodiment of the present disclosure, a hybrid modular DC transformer load current feedforward control method is provided, which quickly responds to changes in load current for a hybrid modular DC transformer HMDCT including at least one PS-DAB and one SR-DAB. The specific control steps are as follows:

[0041] Step S1: According to the selected control mode, obtain the corresponding HMDCT voltage and current measured values;

[0042] Step S2: taking the difference between the measured voltage value and the expected voltage value as the control error, inputting it into the PI controller to obtain the error compensation amount;

[0043] Step S3: constructing the transfer function of the load current feedforward path in real time according to the hardware parameters of the HMDCT and the measured voltage value;

[0044] Step S4: Based on the current measured value, the error compensation amount and the transfer function of the load current feedforward path, an improved feedforward control law is constructed to calculate the expected value of the PS-DAB output current in real time;

[0045] Step S5: Calculate the optimal phase shift of the PS-DAB according to the expected value of the PS-DAB output current, and modulate and generate a PWM wave for controlling the HMDCT in the above mode.

[0046] As an embodiment, a hybrid modular DC transformer load current feedforward control method disclosed in the present invention controls the hybrid modular DC transformer HMDCT in a cycle, which can naturally adapt to the change of power flow direction, quickly respond to the change of load current, and maintain excellent output voltage stability and dynamic performance, such as Figure 1 The specific implementation process is as follows:

[0047] Step 1: At the beginning of a control cycle, the corresponding HMDCT voltage and current measured values ​​are obtained according to the selected control mode.

[0048] HMDCT can contain multiple PS-DABs and SR-DABs. Multiple PS-DABs and SR-DABs in HMDCT are equivalent to one PS-DAB and one SR-DAB, respectively, and the following is obtained: Figure 2 In the HMDCT topology diagram shown in the figure, PS-DAB and SR-DAB are connected in ISOP mode. On the high-voltage side of the HMDCT, the sub-module ports are connected in series, and the side where the sub-module ports are connected in series is referred to as the high-voltage side of the sub-module hereinafter. On the low-voltage side of the HMDCT, the sub-module ports are connected in parallel, and the side where the sub-module ports are connected in parallel is referred to as the low-voltage side of the sub-module hereinafter. The HMDCT supports two control modes: a low-voltage side voltage control mode and a high-voltage side voltage control mode. The low-voltage side voltage control mode takes the high-voltage side as input and the low-voltage side as output, while the high-voltage side voltage control mode takes the low-voltage side as input and the high-voltage side as output.

[0049] If the HMDCT is required to work in the low-voltage side voltage control mode, the measured PS-DAB high-voltage side voltage v 1 、SR-DAB high voltage side voltage v 2 、HMDCT low voltage side output voltage v l 、HMDCT low voltage side load current i l .

[0050] If the HMDCT is required to work in the high-voltage side voltage control mode, the measured PS-DAB high-voltage side voltage v 1 、SR-DAB high voltage side voltage v 2 、The input voltage v on the low voltage side of HMDCT l 、HMDCT high voltage side load current i h .

[0051] Step 2: If the HMDCT is required to work in the low-voltage side voltage control mode, it is sent to the PI controller G PI (s) is the measured value of the low voltage side voltage v l and its expected value V l * The difference (V l * -v l ),like Figure 3 shown.

[0052] The PI controller parameters are based on the first-order integral link (1 / ((C 3 +C 4 )s)) design, the amplitude margin and phase margin can be designed to be around 10dB and 65° respectively; the output of the PI controller is ξ * , that is, the error compensation amount of the PS-DAB expected output current, expressed by the formula:

[0053] ζ * (s) = G PI (s)(V l * (s)-vl (s)) (1)

[0054] Where s is the complex frequency variable in the transfer function, G PI (s) represents the PI controller, v l 、V l * are the measured value and expected value of the low voltage side voltage respectively.

[0055] If the HMDCT is required to work in the high-voltage side voltage control mode, then the voltage is sent to the PI controller G PI (s) is the measured value of the high voltage side voltage v h (=v 1 +v 2 ) and its expected value V h * The difference (V h * -v 1 -v 2 ),like Figure 4 shown.

[0056] The PI controller parameters are based on the first-order integral link (1 / (C 1 s)) design, the amplitude margin and phase margin can be designed to be around 10dB and 65° respectively; the output of the PI controller is ξ * , that is, the error compensation amount of the PS-DAB expected output current, expressed by the formula:

[0057]

[0058] Step 3: Based on the HMDCT transfer function model, HMDCT hardware parameters, and HMDCT input and output voltages, construct the transfer function of the load current feedforward path.

[0059] like Figure 3 As shown in the figure, the load current feedforward path transfer function G in the HMDCT low-voltage side voltage control mode is LCFF (s) is:

[0060]

[0061] In the above formula, v 1 and v 2 is the actual measured voltage value of the PS-DAB high-voltage side and the SR-DAB high-voltage side in the current working state of the HMDCT, C 1||2 is the capacitance C 1 and C 2 The sum of the capacitance values, L eq and R eq are the equivalent DC inductance and resistance respectively, and their expressions are:

[0062]

[0063] Among them, L r is the SR-DAB resonant inductor value, R loss Represents the sum of the on-resistance of the resonant tank, transformer, and MOSFET.

[0064] Since the transfer function G LCFF (s) contains nonlinear time-varying terms v 2 / v 1 To implement this nonlinear transfer function in the controller, we first discretize the transfer function using zero-order hold (ZOH) or bilinear transformation (Tustin) to obtain a transfer function containing v 2 / v 1 The coefficients are then updated in each control cycle of the controller.

[0065] like Figure 4 As shown in the figure, the load current feedforward path transfer function G under the HMDCT high-voltage side voltage control mode is LCFF (s) is:

[0066]

[0067] The above formula does not contain nonlinear time-varying terms, so the transfer function can be discretized once by directly using zero-order hold (ZOH) or bilinear transformation (Tustin), without updating the coefficients of the difference equation every cycle.

[0068] Step 4: According to the disturbance offset method in feedforward control, add the error compensation ζ output by the PI controller in step 2 * , design the following control law and calculate the expected value of the PS-DAB output current:

[0069] like Figure 3 As shown in the figure, the control law in the HMDCT low-voltage side voltage control mode is:

[0070]

[0071] Among them, i l (s) is the measured value of the load current on the low voltage side of HMDCT, ζ * (s) is the PI controller G PI (s) Output error compensation, G LCFF (s) is the transfer function of the load current feedforward path.

[0072] like Figure 4 As shown in the figure, the control law in the HMDCT high-voltage side voltage control mode is:

[0073]

[0074] Among them, i h (s) is the measured value of the load current on the high voltage side of the HMDCT, ζ * (s) is the PI controller G PI (s) Output error compensation, G LCFF (s) is the transfer function of the load current feedforward path.

[0075] Step 5: Output current command based on PS-DAB in step 4 lP > * or hP > * (i.e. the expected value of the PS-DAB output current), the actual measured value of the PS-DAB high-voltage side voltage v in step 1 1 Or the measured value of the voltage on the low voltage side of HMDCT v l , PS-DAB switching frequency f determined during HMDCT hardware design s 、PS-DAB inductor L k , calculate the optimal shift ratio, and get the optimal shift ratio D of PS-DAB P .

[0076] like Figure 3 As shown in the figure, the optimal shift ratio D in the HMDCT low voltage side voltage control mode is P Calculation method:

[0077]

[0078] like Figure 4 As shown in the figure, the optimal shift ratio D in the HMDCT high-voltage side voltage control mode is P Calculation method:

[0079]

[0080] Step 6: D according to the optimal shift ratio P Modulation is performed to generate a single-phase-shifted PWM wave, which drives the switching devices in the HMDCT, and the HMDCT is controlled in the mode, and this control cycle ends.

[0081] Figure 5 The control performance comparison between the control method of this embodiment and the traditional control method under the HMDCT low-voltage side voltage control mode is given; it can be seen that the control method of this embodiment has a faster and more accurate HMDCT power response speed when the load changes, and the HMDCT low-voltage side output voltage v l The overshoot is smaller and the output voltage is more stable.

[0082] ​​ Figure 6 The control performance comparison between the control method of this embodiment and the traditional control method is given in the HMDCT low-voltage side voltage control mode when the load current (power flow) direction is reversed; it can be seen that the control method of this embodiment has a faster and more accurate HMDCT power response speed when the load current suddenly reverses, and the HMDCT low-voltage side output voltage v l The overshoot is smaller and the output voltage is more stable.

[0083] Figure 7 The control performance comparison between the control method of this embodiment and the traditional control method under the HMDCT high-voltage side voltage control mode is given; it can be seen that when the load changes, the control method of this embodiment has a faster and more accurate HMDCT power response speed, and the HMDCT high-voltage side output voltage v h The overshoot is smaller and the output voltage is more stable.

[0084] Example 2

[0085] In one embodiment of the present disclosure, a hybrid modular DC transformer load current feedforward control system is provided, which quickly responds to changes in load current for a hybrid modular DC transformer HMDCT including at least one PS-DAB and one SR-DAB, including:

[0086] The data real-time acquisition module is configured to: obtain the corresponding HMDCT voltage and current measured values ​​according to the selected control mode;

[0087] The error compensation calculation module is configured to: take the difference between the actual voltage value and the expected value as the control error, input it into the PI controller, and obtain the error compensation amount;

[0088] The transfer function building module is configured to: build the transfer function of the load current feed-forward path in real time according to the hardware parameters of the HMDCT and the measured voltage value;

[0089] The current expectation calculation module is configured to: construct an improved feedforward control law based on the current measured value, the error compensation amount and the transfer function of the load current feedforward path, and calculate the expected value of the PS-DAB output current in real time;

[0090] The PWM wave generation module is configured to calculate the optimal shift phase of the PS-DAB according to the expected value of the PS-DAB output current, and modulate and generate a PWM wave for controlling the HMDCT in the mode.

[0091] Example 3

[0092] In one embodiment of the present disclosure, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the hybrid modular DC transformer load current feedforward control method is implemented.

[0093] Example 4

[0094] In one embodiment of the present disclosure, a non-transitory computer-readable storage medium is provided, wherein the non-transitory computer-readable storage medium is used to store computer instructions. When the computer instructions are executed by a processor, the hybrid modular DC transformer load current feedforward control method is implemented.

[0095] Example 5

[0096] In one embodiment of the present disclosure, an electronic device is provided, including: a processor, a memory, and a computer program; wherein the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device is running, the processor executes the computer program stored in the memory, so that the electronic device executes the hybrid modular DC transformer load current feedforward control method.

[0097] The present disclosure is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present disclosure. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0098] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0099] Although the above describes the specific implementation methods of the present disclosure in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present disclosure. Technical personnel in the relevant field should understand that on the basis of the technical solution of the present disclosure, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present disclosure.

Claims

1. A hybrid modular DC transformer load current feedforward control method, characterized in that: For a hybrid modular DC transformer HMDCT including at least one PS-DAB and one SR-DAB, the specific control steps are as follows: According to the selected control mode, the corresponding HMDCT voltage and current measured values ​​are obtained; The difference between the measured voltage value and its expected value is taken as the control error and input into the PI controller to obtain the error compensation amount; According to the hardware parameters of HMDCT and the measured voltage value, the transfer function of the load current feedforward path is constructed in real time; Based on the measured current value, error compensation amount and the transfer function of the load current feedforward path, an improved feedforward control law is constructed to calculate the expected value of the PS-DAB output current in real time; According to the expected value of the PS-DAB output current, the optimal shift phase of the PS-DAB is calculated, and the PWM wave is modulated to generate a PWM wave for controlling the HMDCT in the above mode.

2. A hybrid modular DC transformer load current feedforward control method as claimed in claim 1, characterized in that: The control mode includes a low-voltage side voltage control mode and a high-voltage side voltage control mode; If the HMDCT is required to work in the low-voltage side voltage control mode, the corresponding HMDCT voltage and current measured values ​​are: PS-DAB high-voltage side voltage, SR-DAB high-voltage side voltage, HMDCT low-voltage side output voltage, HMDCT low-voltage side load current, and the difference between the HMDCT low-voltage side output voltage and its expected value is the control error; If the HMDCT is required to operate in the high-voltage side voltage control mode, the corresponding HMDCT voltage and current measured values ​​are: PS-DAB high-voltage side voltage, SR-DAB high-voltage side voltage, HMDCT low-voltage side input voltage, HMDCT high-voltage side load current, and the difference between the high-voltage side voltage measured value and its expected value is the control error, wherein the high-voltage side voltage measured value is the sum of the PS-DAB high-voltage side voltage and the SR-DAB high-voltage side voltage.

3. A hybrid modular DC transformer load current feedforward control method as claimed in claim 1, characterized in that: The error compensation amount is specifically: If the HMDCT is required to work in the low-voltage side voltage control mode, the PI controller is used to calculate the error compensation amount, which is expressed by the formula: ζ * (s)=G PI (s)(V l * (s)-v l (s)) Where s is the complex frequency variable in the transfer function, G PI (s) represents the PI controller, v l 、V l * are the measured value and expected value of the low voltage side voltage respectively; If the HMDCT is required to work in the high-voltage side voltage control mode, the PI controller is used to calculate the error compensation amount, which can be expressed by the formula: Where s is the complex frequency variable in the transfer function, G PI represents the PI controller, v h 、V h * are the measured value and expected value of the high voltage side voltage respectively.

4. A hybrid modular DC transformer load current feedforward control method as claimed in claim 1, characterized in that: The transfer function of the load current feedforward path is specifically: If the HMDCT is required to work in the low-voltage side voltage control mode, the transfer function of the load current feedforward path is: Among them, v1 and v2 are the actual measured values ​​of the PS-DAB high-voltage side voltage and the SR-DAB high-voltage side voltage of the current working state of the HMDCT, C 1||2 is the sum of the capacitances of capacitors C1 and C2, L eq and R eq are the equivalent DC inductance and resistance respectively; If the HMDCT is required to work in the high-voltage side voltage control mode, the transfer function of the load current feedforward path is:

5. A hybrid modular DC transformer load current feedforward control method as claimed in claim 1, characterized in that: The improved feedforward control law is specifically: If the HMDCT is required to work in the low-voltage side voltage control mode, the control law for calculating the expected value of the PS-DAB output current is: Among them, i l (s) is the measured value of the load current on the low voltage side of HMDCT, ζ * (s) is the PI controller G PI (s) Output error compensation, G LCFF (s) is the transfer function of the load current feed-forward path in the low-voltage side voltage control mode; If the HMDCT is required to work in the high-voltage side voltage control mode, the control law for calculating the expected value of the PS-DAB output current is: Among them, i h (s) is the measured value of the load current on the high voltage side of the HMDCT, ζ * (s) is the PI controller G PI (s) Output error compensation, G LCFF (s) is the transfer function of the load current feedforward path under the high-voltage side voltage control mode.

6. A hybrid modular DC transformer load current feedforward control method as claimed in claim 1, characterized in that: The calculation method of the optimal shift ratio is: If the HMDCT is required to work in the low-voltage side voltage control mode, the calculation method of the optimal shift phase ratio is: Where v1 is the measured value of the voltage on the high-voltage side of PS-DAB, f s is the PS-DAB switching frequency, L k For PS-DAB inductor, lP > * is the expected value of PS-DAB output current;​ If the HMDCT is required to work in the high voltage side voltage control mode, then D P The calculation method is: Among them, v l is the measured value of the low-voltage side voltage of HMDCT, f s is the PS-DAB switching frequency, L k For PS-DAB inductor, hP > * is the expected value of PS-DAB output current.​ 7. A hybrid modular DC transformer load current feedforward control system, characterized in that: For a hybrid modular DC transformer HMDCT including at least one PS-DAB and one SR-DAB, fast response to load current changes, including: The data real-time acquisition module is configured to: obtain the corresponding HMDCT voltage and current measured values ​​according to the selected control mode; The error compensation calculation module is configured to: take the difference between the actual voltage value and the expected value as the control error, input it into the PI controller, and obtain the error compensation amount; The transfer function building module is configured to: build the transfer function of the load current feedforward path in real time according to the hardware parameters of the HMDCT and the measured voltage value; The current expectation calculation module is configured to: construct an improved feedforward control law based on the current measured value, the error compensation amount and the transfer function of the load current feedforward path, and calculate the expected value of the PS-DAB output current in real time; The PWM wave generation module is configured to calculate the optimal shift phase of the PS-DAB according to the expected value of the PS-DAB output current, and modulate and generate a PWM wave for controlling the HMDCT in the mode.

8. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, a hybrid modular DC transformer load current feedforward control method as described in any one of claims 1 to 6 is implemented.

9. A non-transitory computer-readable storage medium, characterized in that: The non-transitory computer-readable storage medium is used to store computer instructions. When the computer instructions are executed by the processor, a hybrid modular DC transformer load current feedforward control method as described in any one of claims 1 to 6 is implemented.

10. An electronic device, characterized in that: include: A processor, a memory and a computer program; wherein the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device is running, the processor executes the computer program stored in the memory so that the electronic device executes a hybrid modular DC transformer load current feedforward control method as described in any one of claims 1 to 6.

Images