A hybrid modular dc transformer load current feedforward control method and system

Abstract

The disclosure provides a kind of mixed modular dc transformer load current feedforward control method and system, it is related to dc transformer dynamic performance promotion control technical field, specifically: according to the selected control mode, the corresponding HMDCT voltage and current measured value is obtained;The difference between the voltage measured value and its expected value is input into the PI controller, and the error compensation quantity is obtained;The transfer function of load current feedforward path is constructed in real time;Based on the current measured value, error compensation quantity and the transfer function of load current feedforward path, an improved feedforward control law is constructed, and the expected value of PS-DAB output current is calculated in real time;According to the expected value of PS-DAB output current, the optimal phase shift ratio of PS-DAB is calculated, the PWM wave is generated by modulation, and is used to control HMDCT in the mode;The present application can quickly respond to the change of load current or power, even when the power flow direction mutates, it can also maintain excellent output voltage stability and dynamic performance.

Description

TECHNICAL FIELD

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

[0002] With the rapid growth of various renewable energy sources, loads and energy storage, direct current transformers have become the key hub and core equipment in direct current distribution systems, bearing important functions such as bidirectional power conversion, transmission and electrical isolation between ports and direct current buses, and their performance directly affects the system operation efficiency and the utilization rate of renewable energy.

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

[0004] Although HMDCT has significant advantages in efficiency and controllability in steady-state performance, its dynamic performance is not as good as that of the direct current transformer composed of only PS-DAB. The reason is that SR-DAB works in series resonance mode and dominates the total transmission power of HMDCT, resulting in slow dynamic characteristics similar to SR-DAB. When the output side is connected to a pulsating power load or power source, the slow dynamic characteristics mean greater ripple and overshoot, which can interfere with other devices or force the system to require larger capacity filter capacitors, thereby increasing costs and shortening system life. The above problems seriously limit the further replacement of HMDCT for traditional direct current transformers in microgrids, renewable energy generation and direct current traction, and further restrict the performance improvement of direct current transformers in these fields. Therefore, the dynamic performance of HMDCT needs to be improved. SUMMARY

[0005] The present disclosure proposes a hybrid modular DC transformer load current feedforward control method and system to solve the above problems, 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 containing at least one PS-DAB and one SR-DAB, which quickly responds to changes in load current, and 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 voltage measured value and its expected value is taken as the control error, which is input into the PI controller to obtain the error compensation;

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

[0011] Based on the current measured value, the error compensation, 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 phase shift ratio of the PS-DAB is calculated to generate a PWM wave for controlling the HMDCT in the 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 is provided for a hybrid modular DC transformer HMDCT containing at least one PS-DAB and one SR-DAB, which quickly responds to changes in load current, and includes:

[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 voltage measured value and its expected value as the control error, which is input into the PI controller to obtain the error compensation;

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

[0018] 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 a transfer function of the load current feedforward path, and calculate the expected value of the PS-DAB output current in real time.

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

[0020] According to some embodiments, the present disclosure adopts the technical scheme as follows:

[0021] A computer program product comprising a computer program which, when executed by a processor, implements the hybrid modular DC transformer load current feedforward control method.

[0022] According to some embodiments, the present disclosure adopts the technical scheme as follows:

[0023] A non-transitory computer-readable storage medium for storing computer instructions which, when executed by a processor, implement the hybrid modular DC transformer load current feedforward control method.

[0024] According to some embodiments, the present disclosure adopts the technical scheme as follows:

[0025] An electronic device comprising a processor, a memory and a computer program; wherein the processor is connected with the memory, and the computer program is stored in the memory; when the electronic device is running, the processor executes the computer program stored in the memory, so that the electronic device implements the hybrid modular DC transformer load current feedforward control method.

[0026] Compared with the prior art, the present disclosure has the beneficial effects that:

[0027] The present disclosure establishes a linear "control input-output voltage" equivalent control loop by designing a reasonable improved load current feedforward method, which can approximately eliminate the influence of load current disturbance on the control loop, and can make the output voltage quickly recover to the steady-state value within a few switching periods 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 HMDCT low-voltage side voltage control mode to the high-voltage side voltage control mode. In addition, the present disclosure does not require complex virtual state quantity peak measurement estimation circuits or complex state observers, and only needs to add a second-order filter (i.e. the transfer function of the load current feedforward path) based on the traditional PI control to achieve it, which has the characteristics of simple structure, less calculation and strong engineering practicability. BRIEF DESCRIPTION OF DRAWINGS

[0028] The accompanying drawings, which constitute a part of this disclosure, are incorporated herein for further

[0029] Figure 1 Flow chart for HMDCT low voltage side voltage control mode in embodiment 1.

[0030] Figure 2 Topology diagram for HMDCT in embodiment 1.

[0031] Figure 3 Implementation block diagram and equivalent principle diagram for HMDCT low voltage side voltage control mode in embodiment 1.

[0032] Figure 4 Implementation block diagram and equivalent principle diagram for HMDCT high voltage side voltage control mode in embodiment 1.

[0033] Figure 5 Simulation waveform comparison diagram for HMDCT low voltage side output voltage control mode in embodiment 1, compared with traditional "PI only" and "PI + load current feedforward" methods.

[0034] Figure 6 Simulation waveform comparison diagram for HMDCT low voltage side output voltage control mode in embodiment 1, compared with traditional "PI only" and "PI + load current feedforward" methods when load current (power flow) direction is reversed.

[0035] Figure 7 Simulation waveform comparison diagram for HMDCT high voltage side output voltage control mode in embodiment 1, compared with traditional "PI only" and "PI + load current feedforward" methods. DETAILED DESCRIPTION

[0036] The present disclosure will be further described by way of illustration with reference to the accompanying drawings and embodiments.

[0037] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the present disclosure. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0038] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0039] Embodiment 1

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

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

[0042] Step S2: The difference between the voltage measured value and the expected value thereof is taken as the control error, which is input into the PI controller to obtain the error compensation amount.

[0043] Step S3: According to the hardware parameters of the HMDCT and the voltage measured value, the transfer function of the load current feedforward path is constructed in real time.

[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, and the expected value of the PS-DAB output current is calculated in real time.

[0045] Step S5: According to the expected value of the PS-DAB output current, the optimal phase shift ratio of the PS-DAB is calculated, and the PWM wave is generated by modulation, which is used to control the HMDCT in the mode.

[0046] As an embodiment, the hybrid modular DC transformer load current feedforward control method of the present disclosure can control the hybrid modular DC transformer (HMDCT) in a cycle, which can naturally adapt to changes in tidal direction and quickly respond to changes in load current, and can maintain excellent output voltage stability and dynamic performance, as shown in 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] The HMDCT can include multiple PS-DABs and SR-DABs. The multiple PS-DABs and SR-DABs in the HMDCT are equivalent to one PS-DAB and one SR-DAB, respectively, and the equivalent circuit is as shown inFigure 2 As shown in the HMDCT topology diagram, the PS-DAB and the SR-DAB are connected in the ISOP mode, on the high-voltage side of the HMDCT, the ports of the sub-modules are connected in series, hereinafter referred to as the high-voltage side of the sub-modules, on the low-voltage side of the HMDCT, the ports of the sub-modules are connected in parallel, hereinafter referred to as the low-voltage side of the sub-modules; 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 the input and the low-voltage side as the output, and the high-voltage side voltage control mode takes the low-voltage side as the input and the high-voltage side as the output.

[0049] If the HMDCT is required to work in the low-voltage side voltage control mode, the actual PS-DAB high-voltage side voltage v1, the SR-DAB high-voltage side voltage v2, the HMDCT low-voltage side output voltage v l , and the HMDCT low-voltage side load current i l are measured.

[0050] If the HMDCT is required to work in the high-voltage side voltage control mode, the actual PS-DAB high-voltage side voltage v1, the SR-DAB high-voltage side voltage v2, the HMDCT low-voltage side input voltage v l , and the HMDCT high-voltage side load current i h are measured.

[0051] Step 2: If the HMDCT is required to work in the low-voltage side voltage control mode, the PI controller G PI (s) is fed with the difference (V l l * ) between the actual low-voltage side voltage v l * and the expected low-voltage side voltage V l , as shown in FIG. 4. Figure 3

[0052] The PI controller parameters are designed according to a first-order integral link (1 / ((C3+C4)s)) formed by controlling the low-voltage side capacitors of all the sub-modules in parallel, and the amplitude margin and the phase margin can be designed to be about 10 dB and 65°, respectively; the output of the PI controller is ζ * , that is, the error compensation quantity of the expected output current of the PS-DAB, which is expressed by the formula as follows:

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

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

[0055] If the HMDCT is required to work in the high-voltage side voltage control mode, the PI controller G PI (s) is fed with the difference (V h = v1 + v2) between the measured value v h * of the high-voltage side voltage and its expected value V h * -v1-v2) as shown in FIG. 2. Figure 4

[0056] The PI controller parameters are designed according to a first-order integral link (1 / (C1s)) formed by only controlling the low-voltage side capacitor of the PS-DAB module, and the amplitude margin and the phase margin can be designed to be about 10 dB and 65° respectively; the output of the PI controller is ξ * , i.e. the error compensation amount of the expected output current of the PS-DAB, which is expressed by the formula as follows:

[0057]

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

[0059] As shown in FIG. 3, the transfer function G LCFF (s) of the load current feedforward path under the low-voltage side voltage control mode of the HMDCT is as follows: Figure 3

[0060]

[0061] In the above formula, v1 and v2 are the measured values of the high-voltage side voltage of the PS-DAB and the high-voltage side voltage of the SR-DAB in the current working state of the HMDCT, C 1||2 is the sum of the capacitances of the capacitors C1 and C2, L eq and R eq are respectively the equivalent DC inductance and resistance, and their expressions are as follows:

[0062]

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

[0064] Since the transfer function G LCFF ​​(s) contains nonlinear time-varying terms v2 / v1. To implement this nonlinear transfer function in the controller, the transfer function is first discretized using zero-order hold (ZOH) or bilinear transformation (Tustin) to obtain a difference equation form containing the coefficients of v2 / v1; then the coefficients of the difference equation are updated in each control cycle of the controller.

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

[0066]

[0067] Since the above equation does not contain nonlinear time-varying terms, the transfer function can be discretized once directly using the zero-order hold (ZOH) or bilinear transformation (Tustin), without needing to update the coefficients of the difference equation every period.

[0068] Step 4: Based on the disturbance cancellation method in feedforward control, add the error compensation amount ζ from the PI controller output 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, the control law in the low-voltage side voltage control mode of HMDCT is:

[0070]

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

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

[0073]

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

[0075] Step 5: Based on the PS-DAB output current command in Step 4 lP >​* or hP > * (i.e., the expected value of the PS-DAB output current), the measured value of the PS-DAB high-voltage side voltage v1 or the measured value of the HMDCT low-voltage side voltage v1 in step 1. l The PS-DAB switching frequency f determined during the HMDCT hardware design s PS-DAB Inductor L k The optimal shift ratio D of PS-DAB is calculated by performing the optimal shift ratio calculation. P .

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

[0077]

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

[0079]

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

[0081] Figure 5 A comparison of the control performance of the control method in this embodiment and the traditional control method is presented under the low-voltage side voltage control mode of the HMDCT. It can be seen that the control method in this embodiment exhibits a faster and more accurate power response of the HMDCT under load changes, and the HMDCT low-voltage side output voltage v... l It has less overshoot and a more stable output voltage.

[0082] Figure 6 This paper presents a performance comparison between the control method of this embodiment and the conventional control method when the load current (power flow) direction reverses under the low-voltage side voltage control mode of the HMDCT. It can be seen that the control method of this embodiment exhibits a faster and more accurate HMDCT power response when the load current suddenly reverses, and the HMDCT low-voltage side output voltage v... l It has less overshoot and a more stable output voltage.

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

[0084] Embodiment 2

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

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

[0087] The error compensation calculation module is configured to input the difference between the voltage measured value and the expected value thereof as a control error into a PI controller to obtain an error compensation amount;

[0088] The transfer function construction module is configured to construct a transfer function of a load current feedforward path in real time according to hardware parameters of the HMDCT and the voltage measured value;

[0089] The current expected value 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 an expected value of the PS-DAB output current in real time;

[0090] The PWM wave generation module is configured to calculate an optimal phase shift ratio 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] Embodiment 3

[0092] In an embodiment of the present disclosure, a computer program product is provided, which includes a computer program that, when executed by a processor, implements the hybrid modular DC transformer load current feedforward control method.

[0093] Embodiment 4

[0094] In an embodiment of the present disclosure, a non-transitory computer readable storage medium is provided, which is used to store computer instructions, and the computer instructions, when executed by a processor, implement the hybrid modular DC transformer load current feedforward control method.

[0095] Embodiment 5

[0096] An electronic device is provided in an embodiment of the present disclosure, comprising: a processor, a memory and a computer program; wherein the processor is connected with the memory, and the computer program is stored in the memory; 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 embodiments of the present disclosure. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing devices to produce a machine, so that the instructions executed by the computer or other programmable data processing devices produce a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one flow or multiple flows and / or blocks Figure 1 The functions specified in one flow or multiple flows and / or blocks

[0098] These computer program instructions can also be loaded into a computer or other programmable data processing device to cause a series of operational steps to be executed on the computer or other programmable data processing device to produce a computer-implemented process, so that the instructions executed by the computer or other programmable data processing device provide a process for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one flow or multiple flows and / or blocks Figure 1 The functions specified in one flow or multiple flows and / or blocks

[0099] Although the specific embodiments of the present disclosure are described above with reference to the accompanying drawings, the present disclosure is not limited to the above embodiments, and various modifications or changes can be made by those skilled in the art without departing from the technical solutions of the present disclosure.

Claims

1. A hybrid modular DC transformer load current feed forward control method, characterized in that, The application discloses a hybrid modular DC transformer (HMDCT) comprising at least one phase-shifted double active bridge (PS-DAB) and one series resonant double active bridge (SR-DAB), which can quickly respond to changes in load current, and the specific control steps are as follows: According to the selected control mode, corresponding HMDCT voltage and current measured values are obtained; A difference between the voltage measured value and an expected value thereof is taken as a control error, and is input into a PI controller to obtain an error compensation amount; According to the hardware parameters of the HMDCT and the voltage measured value, a transfer function of a load current feedforward path is constructed in real time; 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, and an expected value of a PS-DAB output current is calculated in real time; According to the expected value of the PS-DAB output current, an optimal phase-shifted ratio of the PS-DAB is calculated, and a PWM wave is generated by modulation, which is used for controlling the HMDCT in the mode; The transfer function of the load current feedforward path is specifically as follows: If the HMDCT is required to work in a low-voltage-side voltage control mode, the transfer function of the load current feedforward path is as follows: wherein, is a complex frequency variable in the transfer function, v 1 and v 2 are the measured values of the PS-DAB high-voltage side voltage and the SR-DAB high-voltage side voltage in the current working state of the HMDCT, is the sum of the capacitances of the PS-DAB high-voltage side capacitor and the SR-DAB high-voltage side capacitor , L eq and R eq are the equivalent direct-current inductance and resistance, respectively; If the HMDCT is required to work in a high-voltage-side voltage control mode, the transfer function of the load current feedforward path is as follows: 。 2. A hybrid modular DC transformer load current feed forward control method as claimed in claim 1, wherein, The control mode comprises 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, corresponding HMDCT voltage and current measured values are as follows: a PS-DAB high-voltage-side voltage, an SR-DAB high-voltage-side voltage, an HMDCT low-voltage-side output voltage and an HMDCT low-voltage-side load current, and a difference between the HMDCT low-voltage-side output voltage and an expected value thereof is taken as a control error. If the HMDCT is required to work in the high-voltage-side voltage control mode, corresponding HMDCT voltage and current measured values are as follows: a PS-DAB high-voltage-side voltage, an SR-DAB high-voltage-side voltage, an HMDCT low-voltage-side input voltage and an HMDCT high-voltage-side load current, and a difference between the high-voltage-side voltage measured value and an expected value thereof is taken as a control error, wherein the high-voltage-side voltage measured value is a sum of the PS-DAB high-voltage-side voltage and the SR-DAB high-voltage-side voltage.

3. The hybrid modular DC transformer load current feed forward control method of claim 1, wherein, The error compensation amount is specifically as follows: If the HMDCT is required to work in the low-voltage-side voltage control mode, the error compensation amount is calculated by using a PI controller, and is expressed by a formula as follows: wherein, is a complex frequency variable in the transfer function, denotes a PI controller, v l , V l * are respectively the measured and desired values of the low voltage side voltage; If the HMDCT is required to work in the high-voltage-side voltage control mode, the error compensation amount is calculated by using a PI controller, and is expressed by a formula as follows: wherein is a complex frequency variable in the transfer function, denotes a PI controller, v h , V h * are the measured and desired values of the high-voltage side voltage, respectively.

4. The hybrid modular DC transformer load current feed forward control method of claim 1, wherein, The improved feedforward control law is specifically as follows: 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 as follows: wherein, is the HMDCT low voltage side load current measured value, is the PI controller the output error compensation amount, is the transfer function of the load current feedforward path under 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 as follows: wherein, is the HMDCT high voltage side load current measured value, is the PI controller the output error compensation amount, is the transfer function of the load current feedforward path under high voltage side voltage control mode.

5. A hybrid modular DC transformer load current feed forward control method as claimed in claim 4, wherein, The calculation method of the optimal phase-shifted ratio is as follows: If the HMDCT is required to work in the low-voltage-side voltage control mode, the calculation method of the optimal phase-shifted ratio is as follows: wherein, is the measured value of the PS-DAB high voltage, is the switching frequency of the PS-DAB, is the inductance of the PS-DAB, is the desired value of the PS-DAB output current; If the HMDCT is required to work in the high voltage side voltage control mode, then The calculation method is: wherein, is the measured value of the low voltage side voltage of the HMDCT, is the switching frequency of the PS-DAB, is the inductance of the PS-DAB, is the desired value of the output current of the PS-DAB.

6. A hybrid modular DC transformer load current feed forward control system, characterized by, The mixed modular DC transformer load current feedforward control method according to any one of claims 1-5 is used for a mixed modular DC transformer HMDCT comprising at least one PS-DAB and one SR-DAB, and can quickly respond to changes in load current, and comprises the following steps: a data real-time acquisition module configured to acquire corresponding HMDCT voltage and current measured values according to a selected control mode; an error compensation calculation module configured to input a difference between the voltage measured value and an expected value thereof as a control error into a PI controller to obtain an error compensation amount; a transfer function construction module configured to construct a transfer function of a load current feedforward path in real time according to hardware parameters of the HMDCT and the voltage measured value; a current expected value calculation module 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 to calculate an expected value of a PS-DAB output current in real time; a PWM wave generation module configured to calculate an optimal phase shift ratio of the PS-DAB according to the expected value of the PS-DAB output current, and to generate a PWM wave for controlling the HMDCT in the mode.

7. A computer program product comprising a computer program, characterized in that, The computer program is executed by a processor to implement the mixed modular DC transformer load current feedforward control method according to any one of claims 1-5.

8. A non-transitory computer-readable storage medium, comprising: The non-transitory computer readable storage medium is used to store computer instructions, which are executed by a processor to implement the mixed modular DC transformer load current feedforward control method according to any one of claims 1-5.

9. An electronic device, comprising: The computer program is executed by a processor to implement the mixed modular DC transformer load current feedforward control method according to any one of claims 1-5. The non-transitory computer readable storage medium is used to store computer instructions, which are executed by a processor to implement the mixed modular DC transformer load current feedforward control method according to any one of claims 1-5. The computer program is executed by a processor to implement the mixed modular DC transformer load current feedforward control method according to any one of claims 1-5. The non-transitory computer readable storage medium is used to store computer instructions, which are executed by a processor to implement the mixed modular DC transformer load current feedforward control method according to any one of claims 1-5. The computer program is executed by a processor to implement the mixed modular DC transformer load current feedforward control method according to any one of claims 1-5. The non-transitory computer readable storage medium is used to store computer instructions, which are executed by a processor to implement the mixed modular DC transformer load current feedforward control method according to any one of claims 1-5.

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