Hybrid MMC transient simulation method and apparatus based on interpolation in blocking mode

Abstract

A hybrid MMC transient simulation method and apparatus based on interpolation in a blocking mode, and a device, which relate to the technical field of power system calculation and analysis. In the method, data in a previous time step of transient simulation of a hybrid MMC is acquired; pre-determination is first performed to obtain a pre-determined blocking working mode; the Thevenin equivalent resistance of a bridge arm is calculated on the basis of the pre-determined blocking working mode; then, a Norton circuit is simulated on the basis of the Thevenin equivalent resistance of the bridge arm, and simulation calculation is performed to obtain the bridge arm voltage of the bridge arm in a current time step, such that the number of switches is greatly reduced, and the simulation efficiency is higher; and finally, whether the pre-determined blocking working mode is correct is verified on the basis of the bridge arm voltage in the current time step and a total capacitive Thevenin equivalent voltage in the previous time step, and an incorrect blocking working mode is corrected, so as to obtain more accurate simulation data of the hybrid MMC. The technical problem of the simulation accuracy being low due to an interpolation problem in existing simulations of the hybrid MMC in a blocking mode of the MMC is solved.

Description

Hybrid MMC transient simulation method and device based on blocking mode interpolation

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on October 31, 2023, with application number 202311438208.7 and invention name “Hybrid MMC transient simulation method and device based on locked mode interpolation”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of power system calculation and analysis, and in particular to a hybrid MMC transient simulation method, device and equipment based on blocking mode interpolation. Background Art

[0003] Hybrid modular multilevel converters (MMCs), composed of a mix of half-bridge and full-bridge submodules, offer a promising future for DC fault ride-through capability and economic efficiency. Accurate and efficient simulation of hybrid MMC electromagnetic transient models is crucial for DC project planning and design, DC engineering, and the safety and stability analysis involved in the dispatching and operation of large AC / DC power grids containing hybrid MMCs.

[0004] Currently, hybrid MMC submodules are used in practical transmission projects. A single bridge arm of a hybrid MMC submodule can contain hundreds of submodules. Considering a valve group consisting of six bridge arms, a station with two poles, and each pole with two high and low valve groups, a two-terminal hybrid MMC DC system can contain tens of thousands of submodules. This large number of switches makes simulation time-consuming. Currently, commercial software simulations of a hybrid MMC DC system consisting of 20,544 submodules take 78 minutes to simulate a 6-second transient process with a 10-µs simulation step, which is insufficient for practical computational requirements. Furthermore, hybrid MMCs include two operating modes: locked and unlocked. In the locked mode, due to the different operating states and complex switching, interpolation issues arise. Accurately simulating the locked mode of the hybrid MMC and achieving accurate and efficient simulations have always been challenging for full-state electromagnetic transient simulations of hybrid MMCs.

[0005] Summary of the Invention

[0006] The embodiments of the present application provide a hybrid MMC transient simulation method, apparatus, and device based on blocking mode interpolation, which are used to solve the technical problem that in the existing hybrid MMC simulation in the MMC blocking mode, interpolation problems exist, resulting in low simulation accuracy.

[0007] In order to achieve the above objectives, the embodiments of the present application provide the following technical solutions:

[0008] On the one hand, a hybrid MMC transient simulation method based on blocking mode interpolation is provided, comprising the following steps:

[0009] Obtain the total submodule voltage of each bridge arm and the Thevenin equivalent voltage history of each submodule capacitor in the previous time step when the hybrid MMC electromagnetic transient model is in the blocking mode; calculate the total capacitance Thevenin equivalent voltage of all submodules in the previous time step based on the Thevenin equivalent voltage history of all submodule capacitors;

[0010] According to the comparison between the total capacitor Thevenin equivalent voltage and the total submodule voltage, the predicted locking working mode of all submodules is obtained; the parameter data of each bridge arm of the hybrid MMC is obtained, and the Thevenin equivalent resistance of the corresponding bridge arm is calculated according to the predicted locking working mode and the parameter data;

[0011] Converting the equivalent voltage source of the hybrid MMC and the Thevenin equivalent resistance of all bridge arms to obtain a Norton circuit of the hybrid MMC; calculating the bridge arm voltage of each bridge arm at the current time step according to the Norton circuit;

[0012] Determining whether the predicted locking working mode of the corresponding bridge arm is correct according to the bridge arm voltage and the total capacitance Thevenin equivalent voltage of the bridge arm; if the prediction is wrong, finding the interpolation time and adjusting the working state of all submodules of the corresponding bridge arm according to the interpolation time;

[0013] The parameter data includes the number of half-bridge sub-modules, the number of full-bridge sub-modules, on-resistance, off-resistance and equivalent resistance of sub-module capacitance of the bridge arm.

[0014] Preferably, obtaining the pre-judgment locking working mode of all submodules according to the comparison between the total capacitor Thevenin equivalent voltage and the total submodule voltage includes:

[0015] If the total submodule voltage is greater than the total capacitor Thevenin equivalent voltage, the pre-judgment locking working mode of all submodules is the forward charging working mode;

[0016] If the total submodule voltage is less than the negative value of the total capacitor Thevenin equivalent voltage, the pre-judgment locking working mode of all submodules is the reverse bypass working mode;

[0017] If the total submodule voltage is not less than the negative value of the total capacitor Thevenin equivalent voltage and the total submodule voltage is not greater than the total capacitor Thevenin equivalent voltage, the pre-judgment locking working mode of all submodules is the cutoff working mode.

[0018] Preferably, obtaining parameter data of each bridge arm of the hybrid MMC, and calculating according to the predicted locking working mode and the parameter data to obtain the Thevenin equivalent resistance of the corresponding bridge arm includes:

[0019] If the pre-judgment locking working mode of all submodules is the forward charging working mode, the Thevenin equivalent resistance of the corresponding bridge arm is calculated using the first equivalent resistance calculation formula according to the parameter data;

[0020] If the pre-judgment blocking working mode of all submodules is the reverse bypass working mode, the Thevenin equivalent resistance of the corresponding bridge arm is calculated using the second equivalent resistance calculation formula according to the parameter data;

[0021] If the pre-judgment blocking working mode of all submodules is the cutoff working mode, the Thevenin equivalent resistance of the corresponding bridge arm is calculated using the third equivalent resistance calculation formula according to the parameter data;

[0022] Wherein, the first equivalent resistance calculation formula is:

[0023] The second equivalent resistance calculation formula is:

[0024] The third equivalent resistance calculation formula:

[0025] Where R smtoteq is the Thevenin equivalent resistance of the bridge arm, N h is the number of half-bridge submodules in the bridge arm, N f is the number of full-bridge submodules in the bridge arm, R on is the on-resistance of the bridge arm, R c is the equivalent resistance of the submodule capacitor of the bridge arm, R off is the off resistance of the bridge arm.

[0026] Preferably, judging whether the predicted locking working mode of the corresponding bridge arm is predicted correctly according to the bridge arm voltage and the total capacitance Thevenin equivalent voltage of the bridge arm, and if the prediction is wrong, finding the interpolation time and adjusting the working state of all submodules of the corresponding bridge arm according to the interpolation time includes:

[0027] According to the prejudgment locking working mode of the bridge arm, the working mode is the forward charging working mode. If the bridge arm voltage is greater than the total capacitor Thevenin equivalent voltage, the prejudgment is correct.

[0028] If the bridge arm voltage is less than the total capacitor Thevenin equivalent voltage, the prediction is wrong, and the moment when the bridge arm voltage is equal to the total capacitor Thevenin equivalent voltage is found as the interpolation moment, and the working state of all sub-modules of the corresponding bridge arm is adjusted to cut off according to the interpolation moment.

[0029] Preferably, judging whether the predicted locking working mode of the corresponding bridge arm is predicted correctly according to the bridge arm voltage and the total capacitance Thevenin equivalent voltage of the bridge arm, and if the prediction is wrong, finding the interpolation time and adjusting the working state of all submodules of the corresponding bridge arm according to the interpolation time includes:

[0030] According to the prejudgment of the bridge arm, the locking working mode is the reverse bypass working mode. If the bridge arm voltage is less than the negative value of the total capacitor Thevenin equivalent voltage, the prejudgment is correct.

[0031] If the bridge arm voltage is greater than the negative value of the total capacitor Thevenin equivalent voltage, the prediction is wrong, and the moment when the bridge arm voltage is equal to the negative value of the total capacitor Thevenin equivalent voltage is found as the interpolation moment, and the working state of all sub-modules of the corresponding bridge arm is adjusted to cut off according to the interpolation moment.

[0032] Preferably, judging whether the predicted locking working mode of the corresponding bridge arm is predicted correctly according to the bridge arm voltage and the total capacitance Thevenin equivalent voltage of the bridge arm, and if the prediction is wrong, finding the interpolation time and adjusting the working state of all submodules of the corresponding bridge arm according to the interpolation time includes:

[0033] According to the prejudgment locking working mode of the bridge arm, the prejudgment is correct if the bridge arm voltage is not less than the negative value of the total capacitance Thevenin equivalent voltage and the bridge arm voltage is not greater than the total capacitance Thevenin equivalent voltage.

[0034] If the bridge arm voltage is greater than the total capacitor Thevenin equivalent voltage, the prediction is wrong, and the moment when the bridge arm voltage is equal to the total capacitor Thevenin equivalent voltage is found as the interpolation moment, and the working state of all submodules of the corresponding bridge arm is adjusted to forward charging according to the interpolation moment;

[0035] If the bridge arm voltage is less than the negative value of the total capacitor Thevenin equivalent voltage, the prediction is wrong, and the moment when the bridge arm voltage is equal to the negative value of the total capacitor Thevenin equivalent voltage is found as the interpolation moment, and the working state of all sub-modules of the corresponding bridge arm is adjusted to reverse bypass according to the interpolation moment.

[0036] In another aspect, a hybrid MMC transient simulation device based on locked-mode interpolation is provided, comprising a data acquisition calculation module, a prejudgment calculation module, a conversion calculation module, and an interpolation execution module;

[0037] The data acquisition and calculation module is used to obtain the total sub-module voltage of each bridge arm and the Thevenin equivalent voltage history of each sub-module capacitor in the previous time step when the hybrid MMC electromagnetic transient model is in the blocking mode; and calculate the total capacitance Thevenin equivalent voltage of all sub-modules in the previous time step based on the Thevenin equivalent voltage history of all sub-module capacitors;

[0038] The pre-judgment calculation module is used to obtain the pre-judgment locking working mode of all sub-modules based on the comparison of the total capacitor Thevenin equivalent voltage and the total sub-module voltage; obtain parameter data of each bridge arm of the hybrid MMC, and calculate the Thevenin equivalent resistance of the corresponding bridge arm based on the pre-judgment locking working mode and the parameter data;

[0039] The conversion calculation module is used to convert the equivalent voltage source of the hybrid MMC and the Thevenin equivalent resistance of all bridge arms to obtain a Norton circuit of the hybrid MMC; and calculate the bridge arm voltage of each bridge arm at the current time step according to the Norton circuit;

[0040] The interpolation execution module is used to determine whether the predicted locking working mode of the corresponding bridge arm is correctly predicted based on the bridge arm voltage and the total capacitance Thevenin equivalent voltage of the bridge arm; if the prediction is wrong, find the interpolation time and adjust the working state of all submodules of the corresponding bridge arm according to the interpolation time;

[0041] The parameter data includes the number of half-bridge sub-modules, the number of full-bridge sub-modules, on-resistance, off-resistance and equivalent resistance of sub-module capacitance of the bridge arm.

[0042] Preferably, the pre-judgment calculation module includes a pre-judgment submodule and an equivalent resistance calculation submodule;

[0043] The prejudgment submodule is configured to: according to the total submodule voltage being greater than the total capacitor Thevenin equivalent voltage, the prejudgment locking working mode of all submodules is a forward charging working mode; according to the total submodule voltage being less than the negative value of the total capacitor Thevenin equivalent voltage, the prejudgment locking working mode of all submodules is a reverse bypass working mode; according to the total submodule voltage being not less than the negative value of the total capacitor Thevenin equivalent voltage and the total submodule voltage being not greater than the total capacitor Thevenin equivalent voltage, the prejudgment locking working mode of all submodules is a cutoff working mode;

[0044] The equivalent resistance calculation submodule is used to calculate the Thevenin equivalent resistance of the corresponding bridge arm according to the first equivalent resistance calculation formula based on the parameter data according to the predicted locking working mode of all submodules being the forward charging working mode; to calculate the Thevenin equivalent resistance of the corresponding bridge arm according to the second equivalent resistance calculation formula based on the parameter data according to the predicted locking working mode of all submodules being the reverse bypass working mode; and to calculate the Thevenin equivalent resistance of the corresponding bridge arm according to the third equivalent resistance calculation formula based on the parameter data according to the predicted locking working mode of all submodules being the cutoff working mode;

[0045] Wherein, the first equivalent resistance calculation formula is:

[0046] The second equivalent resistance calculation formula is:

[0047] The third equivalent resistance calculation formula:

[0048] Where R smtoteq is the Thevenin equivalent resistance of the bridge arm, N h is the number of half-bridge submodules in the bridge arm, N f is the number of full-bridge submodules in the bridge arm, R on is the on-resistance of the bridge arm, R c is the equivalent resistance of the submodule capacitor of the bridge arm, R off is the off resistance of the bridge arm.

[0049] Preferably, the interpolation execution module includes a first judgment submodule, a second judgment submodule and a third judgment submodule;

[0050] The first judgment submodule is used to determine that the prejudgment locking working mode of the bridge arm is a forward charging working mode, and if the bridge arm voltage is greater than the total capacitor Thevenin equivalent voltage, the prejudgment is correct; if the bridge arm voltage is less than the total capacitor Thevenin equivalent voltage, the prejudgment is wrong, and find the time corresponding to the bridge arm voltage being equal to the total capacitor Thevenin equivalent voltage as the interpolation time, and adjust the working state of all submodules of the corresponding bridge arm to cut off according to the interpolation time;

[0051] The second judgment submodule is used to determine that the pre-judgment locking working mode of the bridge arm is a reverse bypass working mode, and if the bridge arm voltage is less than the negative value of the total capacitor Thevenin equivalent voltage, the prejudgment is correct; if the bridge arm voltage is greater than the negative value of the total capacitor Thevenin equivalent voltage, the prejudgment is wrong, and the moment corresponding to the negative value of the total capacitor Thevenin equivalent voltage is found as the interpolation moment, and the working state of all submodules of the corresponding bridge arm is adjusted to cutoff according to the interpolation moment;

[0052] The third judgment submodule is used to determine that the pre-judgment locking working mode of the bridge arm is a cut-off working mode. If the bridge arm voltage is not less than the negative value of the total capacitor Thevenin equivalent voltage and the bridge arm voltage is not greater than the total capacitor Thevenin equivalent voltage, the prejudgment is correct; if the bridge arm voltage is greater than the total capacitor Thevenin equivalent voltage, the prejudgment is wrong, and the moment when the bridge arm voltage is equal to the total capacitor Thevenin equivalent voltage is found as the interpolation moment, and the working state of all submodules of the corresponding bridge arm is adjusted to forward charging according to the interpolation moment; if the bridge arm voltage is less than the negative value of the total capacitor Thevenin equivalent voltage, the prejudgment is wrong, and the moment when the bridge arm voltage is equal to the negative value of the total capacitor Thevenin equivalent voltage is found as the interpolation moment, and the working state of all submodules of the corresponding bridge arm is adjusted to reverse bypass according to the interpolation moment.

[0053] In another aspect, a terminal device is provided, comprising a processor and a memory;

[0054] The memory is used to store program code and transmit the program code to the processor;

[0055] The processor is configured to execute the hybrid MMC transient simulation method based on locked mode interpolation according to the instructions in the program code.

[0056] The hybrid MMC transient simulation method, device and equipment based on locking mode interpolation include obtaining the total submodule voltage of each bridge arm and the Thevenin equivalent voltage history of each submodule capacitor in the previous time step when the hybrid MMC electromagnetic transient model is in the locking mode; calculating the Thevenin equivalent voltage history of all submodule capacitors to obtain the total capacitance Thevenin equivalent voltage of all submodules in the previous time step; obtaining the predicted locking working mode of all submodules by comparing the total capacitance Thevenin equivalent voltage with the total submodule voltage; obtaining the total capacitance Thevenin equivalent voltage of each bridge arm and the Thevenin equivalent voltage history of each submodule capacitor in the previous time step; obtaining the total capacitance Thevenin equivalent voltage of each submodule ... The parameter data of the bridge arm is calculated according to the predicted locking working mode and parameter data to obtain the Thevenin equivalent resistance of the corresponding bridge arm; the equivalent voltage source of the hybrid MMC and the Thevenin equivalent resistance of all bridge arms are converted to obtain the Norton circuit of the hybrid MMC; the bridge arm voltage of each bridge arm at the current time step is calculated according to the Norton circuit; based on the bridge arm voltage and the total capacitance Thevenin equivalent voltage of the bridge arm, it is judged whether the predicted locking working mode of the corresponding bridge arm is predicted correctly; if the prediction is wrong, the interpolation time is found and the working status of all sub-modules of the corresponding bridge arm is adjusted according to the interpolation time. It can be seen from the above technical solution that the embodiment of the present application has the following advantages: the hybrid MMC transient simulation method based on locking mode interpolation first predicts its predicted locking working mode by obtaining the data of the previous time step of the transient simulation of the hybrid MMC, calculates the Thevenin equivalent resistance of the bridge arm according to the pre-judged locking working mode, and then simulates the Norton circuit according to the Thevenin equivalent resistance of the bridge arm to obtain the bridge arm voltage of the bridge arm in the current time step, which greatly reduces the number of switches and has higher simulation efficiency; finally, the pre-judged locking working mode is verified to be correct based on the bridge arm voltage of the current time step and the total capacitance Thevenin equivalent voltage of the previous time step, and the incorrect locking working mode is corrected to obtain more accurate simulation data of the hybrid MMC, which solves the technical problem that the existing simulation of the hybrid MMC in the MMC locking mode has an interpolation problem, resulting in low simulation accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0058] FIG1 is a flowchart of the steps of a hybrid MMC transient simulation method based on blocking mode interpolation according to an embodiment of the present application;

[0059] FIG2 is a topological diagram of a hybrid MMC in a hybrid MMC transient simulation method based on blocking mode interpolation according to an embodiment of the present application;

[0060] 3 is a conversion diagram of an equivalent Thevenin circuit and a Norton circuit of one bridge arm of a hybrid MMC in a hybrid MMC transient simulation method based on locked-mode interpolation according to an embodiment of the present application;

[0061] FIG4 is an equivalent model diagram of a hybrid MMC transient simulation in a hybrid MMC transient simulation method based on blocking mode interpolation according to an embodiment of the present application;

[0062] FIG5 is a schematic diagram of the framework of a hybrid MMC transient simulation device based on blocking mode interpolation according to an embodiment of the present application. DETAILED DESCRIPTION

[0063] In order to make the purpose, features, and advantages of the invention of this application more obvious and easy to understand, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the embodiments described below are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0064] In the description of the embodiments of the present application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0065] In the embodiments of the present application, unless otherwise expressly specified or limited, the terms "installed," "connected," "connected," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections, electrical connections; direct connections, or indirect connections through an intermediate medium; and can refer to internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0066] The embodiments of the present application provide a hybrid MMC transient simulation method, apparatus and device based on locking mode interpolation, which solves the technical problem that in the existing simulation of hybrid MMC in MMC locking mode, there is an interpolation problem, resulting in low simulation accuracy.

[0067] Example 1:

[0068] Figure 1 is a flowchart of the steps of the hybrid MMC transient simulation method based on blocking mode interpolation described in an embodiment of the present application. Figure 2 is a topological diagram of the hybrid MMC used in the hybrid MMC transient simulation method based on blocking mode interpolation described in an embodiment of the present application. In this embodiment, as shown in Figure 2, the three-phase six bridge legs of the hybrid MMC are consistent. The hybrid MMC transient simulation method based on blocking mode interpolation is described using a single bridge leg as an example.

[0069] As shown in FIG1 , an embodiment of the present application provides a hybrid MMC transient simulation method based on blocking mode interpolation, comprising the following steps:

[0070] S1. Obtain the total sub-module voltage of each bridge arm and the Thevenin equivalent voltage history of each sub-module capacitor in the previous time step when the hybrid MMC electromagnetic transient model is in the locking mode; calculate based on the Thevenin equivalent voltage history of all sub-module capacitors to obtain the total capacitance Thevenin equivalent voltage of all sub-modules in the previous time step.

[0071] It should be noted that in step S1, first, the total submodule voltage u of each bridge arm in the previous time step when the hybrid MMC electromagnetic transient model is in the blocking mode is smtot (t-Δt) and the Thevenin equivalent voltage history u of each submodule capacitor ceqi (t-Δt); Secondly, according to the Thevenin equivalent voltage history u of all sub-module capacitors ceqi (t-Δt) is summed to obtain the total capacitance Thevenin equivalent voltage u of all submodules in the previous time step totceq (t-Δt), Δt is the simulation step size, and t is the simulation time step. In this embodiment, when the hybrid MMC is in the blocking mode. Since in the blocking mode, regardless of the full-bridge submodule or half-bridge submodule of the hybrid MMC, the current of all submodules is the same, all submodules in the same bridge arm have the same blocking working mode, which includes forward charging, reverse bypass and cutoff. First, obtain the total submodule voltage u of each bridge arm in the previous time step smtot (t-Δt) and the Thevenin equivalent voltage history u of all submodule capacitors ceqi (t-Δt), if all submodules of the hybrid MMC are in the forward charging state, calculate the value u of the total capacitance Thevenin equivalent voltage of all submodules in the previous time step totceq (t-Δt), that is:

[0072] Where N is the total number of submodules in the bridge arm.

[0073] S2. Determine the predicted blocking operating mode for all submodules by comparing the total capacitor Thevenin equivalent voltage with the total submodule voltage; obtain parameter data for each bridge arm of the hybrid MMC, and calculate the Thevenin equivalent resistance of the corresponding bridge arm based on the predicted blocking operating mode and parameter data. The parameter data includes the number of half-bridge submodules, the number of full-bridge submodules, the on-resistance, the off-resistance, and the submodule capacitor equivalent resistance.

[0074] It should be noted that in step S2, the u obtained in step S1 is totceq (t-Δt) and u smtot By comparing (t-Δt), the blocking working mode of all submodules is predicted, and then the Thevenin equivalent resistance of the corresponding bridge arm is calculated according to the corresponding predicted blocking working mode and parameter data, so that the Thevenin equivalent resistance R of the six bridge arms in the hybrid MMC can be obtained. smtoteq .

[0075] FIG3 is a conversion diagram of an equivalent Thevenin circuit and a Norton circuit of one bridge arm of a hybrid MMC in a hybrid MMC transient simulation method based on locked-mode interpolation according to an embodiment of the present application.

[0076] S3. Convert the equivalent voltage source of the hybrid MMC and the Thevenin equivalent resistance of all bridge arms to obtain the Norton circuit of the hybrid MMC; and calculate the bridge arm voltage of each bridge arm at the current time step based on the Norton circuit.

[0077] It should be noted that, in the blocking mode, regardless of whether it is a full-bridge sub-module or a half-bridge sub-module of the hybrid MMC, the current of all sub-modules is the same, so all sub-modules in the same bridge arm have the same blocking working mode. Therefore, the equivalent voltage source U of a bridge arm in the hybrid MMC as shown in FIG3 is S And the Thevenin equivalent resistance R of the corresponding bridge arm is converted to obtain the equivalent current I S and the equivalent output resistance G form a Norton circuit of a hybrid MMC. In the Norton circuit, the voltage of the bridge arm is I S In this embodiment, the hybrid MMC transient simulation method based on locked mode interpolation converts the Thevenin circuit of the hybrid MMC into a Norton circuit. The Norton circuit is a circuit in which the bridge arm inductance of the hybrid MMC is equivalent to a resistor and a historical current source in parallel through an implicit trapezoidal integration method.

[0078] S4. Determine whether the predicted locking working mode of the corresponding bridge arm is correct based on the bridge arm voltage and the total capacitor Thevenin equivalent voltage of the bridge arm; if the prediction is wrong, find the interpolation time and adjust the working status of all sub-modules of the corresponding bridge arm according to the interpolation time.

[0079] It should be noted that in step S4, based on the comparison of the bridge arm voltage of the current time step and the total capacitance Thevenin equivalent voltage, it is judged whether the predicted locking working mode of all sub-modules is correct. If the prediction is correct, the next time step simulation calculation is performed; if the prediction is wrong, it is necessary to obtain the correct locking working mode based on the bridge arm voltage of the current time step and the total capacitance Thevenin equivalent voltage of all sub-module capacitors, and interpolate to find the moment when the working mode changes and adjust the working state of all sub-modules of the bridge arm. Among them, the working state includes three types: forward charging, reverse bypass and cutoff.

[0080] In an embodiment of the present application, the hybrid MMC transient simulation method based on locked-mode interpolation can use variable resistors to simulate different locked-mode operating modes of the hybrid MMC, and only one variable resistor is used in one bridge arm to simultaneously consider the half-bridge submodule and the full-bridge submodule. Compared with the existing method of adding diodes or virtual diodes to consider interpolation in the Thevenin circuit, the hybrid MMC transient simulation method based on locked-mode interpolation greatly reduces the number of switches. While achieving the same simulation accuracy, the simulation efficiency is higher, and the program implementation is simple and easy to implement. Without losing simulation accuracy, the hybrid MMC transient simulation method based on locked-mode interpolation has high computational efficiency and simple program implementation, and is very suitable for the development of MMC electromagnetic transient models for actual engineering calculations.

[0081] The present application provides a hybrid MMC transient simulation method based on locking mode interpolation, which includes obtaining the total submodule voltage of each bridge arm and the Thevenin equivalent voltage history of each submodule capacitor in the previous time step when the hybrid MMC electromagnetic transient model is in the locking mode; calculating the Thevenin equivalent voltage history of all submodule capacitors to obtain the total capacitance Thevenin equivalent voltage of all submodules in the previous time step; obtaining the predicted locking working mode of all submodules by comparing the total capacitance Thevenin equivalent voltage with the total submodule voltage; obtaining the total capacitance Thevenin equivalent voltage of each bridge arm and the total capacitance of each submodule capacitor in the previous time step; obtaining the total capacitance Thevenin equivalent voltage of each bridge arm and the total capacitance of each submodule ...; obtaining the total capacitance Thevenin equivalent voltage of each bridge arm and the total capacitance of each submodule; obtaining the total capacitance Thevenin equivalent voltage of each bridge arm and the total capacitance of each submodule; obtaining the total capacitance Thevenin equivalent voltage of each bridge arm and the total capacitance of each submodule; obtaining the total capacitance Thevenin equivalent voltage of each bridge arm and the total capacitance of each submodule; obtaining the total capacitance Thevenin equivalent voltage of each bridge arm and the total capacitance of each submodule; obtaining the total capacitance Thevenin equivalent voltage of each bridge arm and the total capacitance of each submodule; obtaining the total capacitance Thevenin equivalent voltage of each bridge arm and The parameter data of the bridge arm is calculated according to the predicted locking working mode and parameter data to obtain the Thevenin equivalent resistance of the corresponding bridge arm; the equivalent voltage source of the hybrid MMC and the Thevenin equivalent resistance of all bridge arms are converted to obtain the Norton circuit of the hybrid MMC; the bridge arm voltage of each bridge arm at the current time step is calculated according to the Norton circuit; based on the bridge arm voltage and the total capacitance Thevenin equivalent voltage of the bridge arm, it is judged whether the predicted locking working mode of the corresponding bridge arm is predicted correctly; if the prediction is wrong, the interpolation time is found and the working status of all sub-modules of the corresponding bridge arm is adjusted according to the interpolation time. The hybrid MMC transient simulation method based on locking mode interpolation first predicts its predicted locking working mode by obtaining the data of the previous time step of the transient simulation of the hybrid MMC, calculates the Thevenin equivalent resistance of the bridge arm according to the predicted locking working mode, and then simulates the Norton circuit based on the Thevenin equivalent resistance of the bridge arm to obtain the bridge arm voltage of the bridge arm in the current time step, which greatly reduces the number of switches and has higher simulation efficiency; finally, the correctness of the predicted locking working mode is verified according to the bridge arm voltage of the current time step and the total capacitance Thevenin equivalent voltage of the previous time step, and the incorrect locking working mode is corrected to obtain more accurate simulation data of the hybrid MMC, which solves the technical problem that the existing simulation of the hybrid MMC in the MMC locking mode has an interpolation problem, resulting in low simulation accuracy.

[0082] FIG4 is an equivalent model diagram of a hybrid MMC transient simulation in a hybrid MMC transient simulation method based on blocking mode interpolation according to an embodiment of the present application.

[0083] In one embodiment of the present application, the predicted locking working mode of all submodules is obtained by comparing the total capacitor Thevenin equivalent voltage with the total submodule voltage, including:

[0084] If the total submodule voltage is greater than the total capacitor Thevenin equivalent voltage, the pre-judgment locking working mode of all submodules is the forward charging working mode;

[0085] If the total submodule voltage is less than the negative value of the total capacitor Thevenin equivalent voltage, the pre-judgment locking working mode of all submodules is the reverse bypass working mode;

[0086] If the total submodule voltage is not less than the negative value of the total capacitor Thevenin equivalent voltage and the total submodule voltage is not greater than the total capacitor Thevenin equivalent voltage, the pre-judgment locking working mode of all submodules is the cutoff working mode.

[0087] It should be noted that, as shown in Figure 4, the hybrid MMC transient simulation method based on locking mode interpolation predicts the locking working mode of all sub-modules according to the total sub-module voltage of each bridge arm and the total capacitance Thevenin equivalent voltage of all sub-modules, and records it as the predicted locking working mode, and then calculates the Thevenin equivalent resistance of all sub-modules in the entire bridge arm.

[0088] In the embodiment of the present application, the parameter data of each bridge arm of the hybrid MMC is obtained, and the Thevenin equivalent resistance of the corresponding bridge arm is obtained by calculation based on the predicted locking working mode and the parameter data.

[0089] If the pre-judgment locking working mode of all submodules is the forward charging working mode, the Thevenin equivalent resistance of the corresponding bridge arm is calculated using the first equivalent resistance calculation formula according to the parameter data;

[0090] If the pre-judgment blocking working mode of all submodules is the reverse bypass working mode, the Thevenin equivalent resistance of the corresponding bridge arm is calculated using the second equivalent resistance calculation formula according to the parameter data;

[0091] If the pre-judgment blocking working mode of all submodules is the cut-off working mode, the Thevenin equivalent resistance of the corresponding bridge arm is calculated using the third equivalent resistance calculation formula according to the parameter data;

[0092] Among them, the first equivalent resistance calculation formula is:

[0093] The second equivalent resistance calculation formula is:

[0094] The third equivalent resistance calculation formula:

[0095] Where R smtoteq is the Thevenin equivalent resistance of the bridge arm, N h is the number of half-bridge submodules in the bridge arm, N f is the number of full-bridge submodules in the bridge arm, R on is the on-resistance of the bridge arm, R c is the equivalent resistance of the submodule capacitor of the bridge arm, R off is the off resistance of the bridge arm.

[0096] It should be noted that when u smtot (t-Δt)>u totceqWhen (t-Δt), it is determined that the pre-judgment locking working mode of all submodules is the forward charging working mode, and the first equivalent resistance calculation formula is used to calculate the Thevenin equivalent resistance of the corresponding bridge arm; when u smtot (t-Δt)<-u totceq When (t-Δt), it is judged that the pre-judgment locking working mode of all submodules is the reverse bypass working mode, and the second equivalent resistance calculation formula is used to calculate the Thevenin equivalent resistance of the corresponding bridge arm; when -u totceq (t-Δt)≤u smtot (t)≤u totceq When (t-Δt), it is determined that the pre-judgment blocking working mode of all submodules is the cut-off working mode, and the Thevenin equivalent resistance of the corresponding bridge arm is calculated using the third equivalent resistance calculation formula.

[0097] In one embodiment of the present application, judging whether the predicted locking working mode of the corresponding bridge arm is predicted correctly according to the bridge arm voltage and the total capacitance Thevenin equivalent voltage of the bridge arm, and if the prediction is wrong, finding the interpolation time and adjusting the working state of all submodules of the corresponding bridge arm according to the interpolation time includes:

[0098] According to the predicted locking working mode of the bridge arm, the working mode is the forward charging working mode. If the bridge arm voltage is greater than the total capacitor Thevenin equivalent voltage, the prediction is correct; if the bridge arm voltage is less than the total capacitor Thevenin equivalent voltage, the prediction is wrong. The moment when the bridge arm voltage is equal to the total capacitor Thevenin equivalent voltage is found as the interpolation moment, and the working state of all sub-modules of the corresponding bridge arm is adjusted to cutoff according to the interpolation moment;

[0099] According to the predicted locking working mode of the bridge arm, the reverse bypass working mode is used. If the bridge arm voltage is less than the negative value of the total capacitor Thevenin equivalent voltage, the prediction is correct; if the bridge arm voltage is greater than the negative value of the total capacitor Thevenin equivalent voltage, the prediction is wrong. The moment when the bridge arm voltage is equal to the negative value of the total capacitor Thevenin equivalent voltage is found as the interpolation moment, and the working state of all sub-modules of the corresponding bridge arm is adjusted to cutoff according to the interpolation moment.

[0100] According to the predicted locking working mode of the bridge arm, the working mode is the cutoff working mode. If the bridge arm voltage is not less than the negative value of the total capacitor Thevenin equivalent voltage and the bridge arm voltage is not greater than the total capacitor Thevenin equivalent voltage, the prediction is correct; if the bridge arm voltage is greater than the total capacitor Thevenin equivalent voltage, the prediction is wrong, and the moment when the bridge arm voltage is equal to the total capacitor Thevenin equivalent voltage is found as the interpolation moment, and the working state of all sub-modules of the corresponding bridge arm is adjusted to forward charging according to the interpolation moment; if the bridge arm voltage is less than the negative value of the total capacitor Thevenin equivalent voltage, the prediction is wrong, and the moment when the bridge arm voltage is equal to the negative value of the total capacitor Thevenin equivalent voltage is found as the interpolation moment, and the working state of all sub-modules of the corresponding bridge arm is adjusted to reverse bypass according to the interpolation moment.

[0101] It should be noted that, as shown in FIG4 , the hybrid MMC transient simulation method based on the blocking mode interpolation is based on the bridge arm voltage u of each bridge arm at the current time step. smtot (t), judge whether the pre-judgment locking working mode of all submodules is correct and whether interpolation is required. In this embodiment, the pre-judgment locking working mode is judged separately. According to the pre-judgment locking working mode of the bridge arm is the forward charging working mode, when u smtot (t)>u totceq (t-Δt), the predicted blocking mode is correct, and the next step is to calculate the hybrid MMC transient simulation; when u smtot (t) totceq (t-Δt), the predicted locking mode is wrong, and interpolation is used to find u smtot (t) = u totceq (t-Δt) corresponds to the interpolation time t0, at which the working state of all submodules of the bridge arm is adjusted to cutoff. According to the prejudgment blocking working mode of the bridge arm, the reverse bypass working mode is used. When u smtot (t)<-u totceq (t-Δt), the predicted blocking mode is correct, and the next step is to calculate the hybrid MMC transient simulation; when u smtot (t)>-u totceq (t-Δt), the predicted locking mode is wrong, and u smtot (t)=-u totceq (t-Δt) corresponds to the interpolation time t0, at which the working state of all submodules of the bridge arm is adjusted to cut-off. According to the prejudgment blocking working mode of the bridge arm, the cut-off working mode is set. When -u totceq (t-Δt)≤u smtot (t)≤u totceq (t-Δt), the predicted blocking mode is correct, and the next step is to calculate the hybrid MMC transient simulation; when u smtot (t)>u totceq (t-Δt), the predicted locking mode is wrong, and u smtot (t) = u totceq At the interpolation time t0 corresponding to (t-Δt), the working state of all submodules of the bridge arm is adjusted to forward charging. smtot (t)<-u totceq (t-Δt), the predicted locking mode is wrong, and u smtot (t)=-u totceq The interpolation time t0 corresponding to (t-Δt) is adjusted at the interpolation time t0 to adjust the working state of all sub-modules of the bridge arm to reverse bypass.​

[0102] Example 2:

[0103] FIG5 is a schematic diagram of the framework of a hybrid MMC transient simulation device based on blocking mode interpolation according to an embodiment of the present application.

[0104] As shown in FIG5 , the embodiment of the present application provides a hybrid MMC transient simulation device based on locked mode interpolation, comprising a data acquisition calculation module 10 , a pre-judgment calculation module 20 , a conversion calculation module 30 , and an interpolation execution module 40 ;

[0105] The data acquisition and calculation module 10 is used to obtain the total submodule voltage of each bridge arm and the Thevenin equivalent voltage history of each submodule capacitor in the previous time step when the hybrid MMC electromagnetic transient model is in the blocking mode; and calculate the total capacitance Thevenin equivalent voltage of all submodules in the previous time step based on the Thevenin equivalent voltage history of all submodule capacitors;

[0106] The prejudgment calculation module 20 is used to obtain the prejudgment locking working mode of all submodules based on the comparison of the total capacitor Thevenin equivalent voltage and the total submodule voltage; obtain the parameter data of each bridge arm of the hybrid MMC, and calculate the Thevenin equivalent resistance of the corresponding bridge arm based on the prejudgment locking working mode and the parameter data;

[0107] The conversion calculation module 30 is used to convert the equivalent voltage source of the hybrid MMC and the Thevenin equivalent resistance of all bridge arms to obtain the Norton circuit of the hybrid MMC; and calculate the bridge arm voltage of each bridge arm at the current time step based on the Norton circuit;

[0108] The interpolation execution module 40 is used to determine whether the predicted locking working mode of the corresponding bridge arm is correct based on the bridge arm voltage and the total capacitance Thevenin equivalent voltage of the bridge arm; if the prediction is wrong, find the interpolation time and adjust the working state of all submodules of the corresponding bridge arm according to the interpolation time;

[0109] The parameter data includes the number of half-bridge sub-modules, the number of full-bridge sub-modules, on-resistance, off-resistance and equivalent resistance of sub-module capacitance of the bridge arm.

[0110] In the embodiment of the present application, the pre-judgment calculation module 20 includes a pre-judgment submodule and an equivalent resistance calculation submodule;

[0111] A prejudgment submodule, configured to set the prejudgment locking working mode of all submodules to a forward charging working mode based on the total submodule voltage being greater than the total capacitor Thevenin equivalent voltage; set the prejudgment locking working mode of all submodules to a reverse bypass working mode based on the total submodule voltage being less than the negative value of the total capacitor Thevenin equivalent voltage; and set the prejudgment locking working mode of all submodules to a cutoff working mode based on the total submodule voltage being not less than the negative value of the total capacitor Thevenin equivalent voltage and the total submodule voltage being not greater than the total capacitor Thevenin equivalent voltage.

[0112] An equivalent resistance calculation submodule, configured to calculate, based on the parameter data, a first equivalent resistance calculation formula according to the predicted locking working mode of all submodules as a forward charging working mode, to obtain the Thevenin equivalent resistance of the corresponding bridge arm; to calculate, based on the parameter data, a second equivalent resistance calculation formula according to the predicted locking working mode of all submodules as a reverse bypass working mode, to obtain the Thevenin equivalent resistance of the corresponding bridge arm; and to calculate, based on the parameter data, a third equivalent resistance calculation formula according to the parameter data, to obtain the Thevenin equivalent resistance of the corresponding bridge arm.

[0113] Among them, the first equivalent resistance calculation formula is:

[0114] The second equivalent resistance calculation formula is:

[0115] The third equivalent resistance calculation formula:

[0116] Where R smtoteq is the Thevenin equivalent resistance of the bridge arm, N h is the number of half-bridge submodules in the bridge arm, N f is the number of full-bridge submodules in the bridge arm, R on is the on-resistance of the bridge arm, R c is the equivalent resistance of the submodule capacitor of the bridge arm, R off is the off resistance of the bridge arm.

[0117] In the embodiment of the present application, the interpolation execution module 30 includes a first judgment submodule, a second judgment submodule and a third judgment submodule;

[0118] The first judgment submodule is used to determine that the pre-judgment locking working mode of the bridge arm is a forward charging working mode. If the bridge arm voltage is greater than the total capacitor Thevenin equivalent voltage, the prejudgment is correct; if the bridge arm voltage is less than the total capacitor Thevenin equivalent voltage, the prejudgment is wrong, and the time corresponding to the bridge arm voltage being equal to the total capacitor Thevenin equivalent voltage is found as the interpolation time, and the working state of all submodules of the corresponding bridge arm is adjusted to cutoff according to the interpolation time;

[0119] The second judgment submodule is used to determine that the pre-judgment locking working mode of the bridge arm is a reverse bypass working mode. If the bridge arm voltage is less than the negative value of the total capacitor Thevenin equivalent voltage, the prejudgment is correct; if the bridge arm voltage is greater than the negative value of the total capacitor Thevenin equivalent voltage, the prejudgment is wrong, and the moment corresponding to the negative value of the bridge arm voltage equal to the total capacitor Thevenin equivalent voltage is found as the interpolation moment, and the working state of all submodules of the corresponding bridge arm is adjusted to cutoff according to the interpolation moment;

[0120] The third judgment submodule is used to lock the working mode as the cutoff working mode according to the predicted locking mode of the bridge arm. If the bridge arm voltage is not less than the negative value of the total capacitor Thevenin equivalent voltage and the bridge arm voltage is not greater than the total capacitor Thevenin equivalent voltage, the prediction is correct; if the bridge arm voltage is greater than the total capacitor Thevenin equivalent voltage, the prediction is wrong, and the corresponding moment when the bridge arm voltage is equal to the total capacitor Thevenin equivalent voltage is found as the interpolation moment, and the working state of all sub-modules of the corresponding bridge arm is adjusted to forward charging according to the interpolation moment; if the bridge arm voltage is less than the negative value of the total capacitor Thevenin equivalent voltage, the prediction is wrong, and the corresponding moment when the bridge arm voltage is equal to the negative value of the total capacitor Thevenin equivalent voltage is found as the interpolation moment, and the working state of all sub-modules of the corresponding bridge arm is adjusted to reverse bypass according to the interpolation moment.

[0121] It should be noted that the contents of the modules in the apparatus of Example 2 correspond to the steps of the method of Example 1. The contents of the hybrid MMC transient simulation method based on closed-mode interpolation have been described in Example 1, and the steps of the hybrid MMC transient simulation method based on closed-mode interpolation will not be described in detail in this embodiment.

[0122] Example 3:

[0123] An embodiment of the present application provides a terminal device, including a processor and a memory;

[0124] A memory, configured to store program codes and transmit the program codes to a processor;

[0125] The processor is configured to execute the hybrid MMC transient simulation method based on locked mode interpolation according to instructions in the program code.

[0126] It should be noted that the processor is configured to execute the steps of the aforementioned embodiment of the method for rapid startup of electromagnetic transient simulation of a modular multilevel converter according to the instructions in the program code. Alternatively, the processor implements the functions of the modules / units in the aforementioned system / device embodiments when executing the computer program.

[0127] For example, a computer program may be divided into one or more modules / units, one or more of which are stored in a memory and executed by a processor to complete the present application. One or more modules / units may be a series of computer program instruction segments capable of performing specific functions, and the instruction segments are used to describe the execution process of the computer program in a terminal device.

[0128] Terminal devices can be computing devices such as desktop computers, laptops, PDAs, and cloud servers. Terminal devices may include, but are not limited to, processors and memory. Those skilled in the art will appreciate that this does not constitute a limitation on terminal devices and may include more or fewer components than shown, or a combination of certain components, or different components. For example, terminal devices may also include input / output devices, network access devices, buses, and the like.

[0129] The processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (dSIC), field-programmable gate arrays (FPGAs), other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0130] The memory can be an internal storage unit of a terminal device, such as a hard drive or memory of the terminal device. The memory can also be an external storage device of the terminal device, such as a plug-in hard drive, a Smart Memory Card (SMC), a Secure Digital (SD) card, a flash memory card, etc. Furthermore, the memory can include both the internal storage unit of the terminal device and an external storage device. The memory is used to store computer programs and other programs and data required by the terminal device. The memory can also be used to temporarily store data that has been output or is about to be output.

[0131] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0132] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0133] 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, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0134] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0135] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RdM), a magnetic disk or an optical disk.

[0136] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above 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 embodiments of the present application.

Claims

1. A hybrid MMC transient simulation method based on blocking mode interpolation, characterized in that: The following steps are involved: Obtain the total submodule voltage of each bridge arm and the Thevenin equivalent voltage history of each submodule capacitor in the previous time step when the hybrid MMC electromagnetic transient model is in the blocking mode; calculate according to the Thevenin equivalent voltage history of all submodule capacitors to obtain the total capacitance Thevenin equivalent voltage of all submodules in the previous time step; According to the comparison between the total capacitor Thevenin equivalent voltage and the total submodule voltage, the predicted locking working mode of all submodules is obtained; the parameter data of each bridge arm of the hybrid MMC is obtained, and the Thevenin equivalent resistance of the corresponding bridge arm is obtained according to the predicted locking working mode and the parameter data; According to the equivalent voltage source of the hybrid MMC and the Thevenin equivalent resistance of all bridge arms, a Norton circuit of the hybrid MMC is obtained by conversion; and according to the Norton circuit, a bridge arm voltage of each bridge arm at the current time step is calculated; Judging whether the predicted locking working mode of the corresponding bridge arm is predicted correctly according to the bridge arm voltage of the bridge arm and the total capacitance Thevenin equivalent voltage; if the prediction is wrong, finding the interpolation time and adjusting the working state of all submodules of the corresponding bridge arm according to the interpolation time; The parameter data includes the number of half-bridge sub-modules, the number of full-bridge sub-modules, on-resistance, off-resistance and equivalent resistance of sub-module capacitance of the bridge arm.

2. The hybrid MMC transient simulation method based on blocking mode interpolation according to claim 1 is characterized in that: According to the comparison between the total capacitor Thevenin equivalent voltage and the total submodule voltage, the pre-judgment locking working mode of all submodules is obtained, including: If the total submodule voltage is greater than the total capacitor Thevenin equivalent voltage, the pre-judgment locking working mode of all submodules is a forward charging working mode; If the total submodule voltage is less than the negative value of the total capacitor Thevenin equivalent voltage, the prejudgment locking working mode of all submodules is the reverse bypass working mode; If the total submodule voltage is not less than the negative value of the total capacitor Thevenin equivalent voltage and the total submodule voltage is not greater than the total capacitor Thevenin equivalent voltage, the pre-judgment locking working mode of all submodules is the cut-off working mode.

3. The hybrid MMC transient simulation method based on blocking mode interpolation according to claim 2 is characterized in that: Obtaining parameter data of each bridge arm of the hybrid MMC, and calculating according to the predicted locking working mode and the parameter data to obtain the Thevenin equivalent resistance of the corresponding bridge arm includes: If the pre-judgment locking working mode of all submodules is the forward charging working mode, the Thevenin equivalent resistance of the corresponding bridge arm is calculated using the first equivalent resistance calculation formula according to the parameter data; If the pre-judgment blocking working mode of all submodules is the reverse bypass working mode, the Thevenin equivalent resistance of the corresponding bridge arm is calculated using the second equivalent resistance calculation formula according to the parameter data; If the pre-judgment blocking working mode of all submodules is the cut-off working mode, the Thevenin equivalent resistance of the corresponding bridge arm is calculated using the third equivalent resistance calculation formula according to the parameter data; Wherein, the first equivalent resistance calculation formula is: The second equivalent resistance calculation formula is: The third equivalent resistance calculation formula: In the formula, R smtoteq is the Thevenin equivalent resistance of the bridge arm, N h is the number of half-bridge submodules in the bridge arm, N f is the number of full-bridge submodules in the bridge arm, R on is the on-resistance of the bridge arm, R c is the equivalent resistance of the submodule capacitor of the bridge arm, R off is the off resistance of the bridge arm.

4. The hybrid MMC transient simulation method based on blocking mode interpolation according to claim 1 is characterized in that: Judging whether the predicted locking working mode of the corresponding bridge arm is predicted correctly according to the bridge arm voltage and the total capacitance Thevenin equivalent voltage of the bridge arm, and if the prediction is wrong, finding the interpolation time and adjusting the working state of all submodules of the corresponding bridge arm according to the interpolation time includes: According to the prejudgment locking working mode of the bridge arm, the working mode is a forward charging working mode. If the bridge arm voltage is greater than the total capacitor Thevenin equivalent voltage, the prejudgment is correct. If the bridge arm voltage is less than the total capacitor Thevenin equivalent voltage, it is predicted that an error occurs, and the time corresponding to the bridge arm voltage being equal to the total capacitor Thevenin equivalent voltage is found as the interpolation time, and the working state of all sub-modules of the corresponding bridge arm is adjusted to cutoff according to the interpolation time.

5. The hybrid MMC transient simulation method based on blocking mode interpolation according to claim 1 is characterized in that: Judging whether the predicted locking working mode of the corresponding bridge arm is predicted correctly according to the bridge arm voltage and the total capacitance Thevenin equivalent voltage of the bridge arm, and if the prediction is wrong, finding the interpolation time and adjusting the working state of all submodules of the corresponding bridge arm according to the interpolation time includes: According to the predicted locking working mode of the bridge arm, the reverse bypass working mode is predicted, and if the bridge arm voltage is less than the negative value of the total capacitor Thevenin equivalent voltage, the prediction is correct; If the bridge arm voltage is greater than the negative value of the total capacitor Thevenin equivalent voltage, it is predicted that an error occurs, and the moment when the bridge arm voltage is equal to the negative value of the total capacitor Thevenin equivalent voltage is found as the interpolation moment, and the working state of all sub-modules of the corresponding bridge arm is adjusted to cutoff according to the interpolation moment.

6. The hybrid MMC transient simulation method based on blocking mode interpolation according to claim 1 is characterized in that: Judging whether the predicted locking working mode of the corresponding bridge arm is predicted correctly according to the bridge arm voltage and the total capacitance Thevenin equivalent voltage of the bridge arm, and if the prediction is wrong, finding the interpolation time and adjusting the working state of all submodules of the corresponding bridge arm according to the interpolation time includes: According to the prejudgment locking working mode of the bridge arm, the prejudgment is correct if the bridge arm voltage is not less than the negative value of the total capacitance Thevenin equivalent voltage and the bridge arm voltage is not greater than the total capacitance Thevenin equivalent voltage. If the bridge arm voltage is greater than the total capacitor Thevenin equivalent voltage, it is predicted that an error occurs, and the time corresponding to the bridge arm voltage being equal to the total capacitor Thevenin equivalent voltage is found as the interpolation time, and the working state of all submodules of the corresponding bridge arm is adjusted to forward charging according to the interpolation time; If the bridge arm voltage is less than the negative value of the total capacitor Thevenin equivalent voltage, it is predicted that an error occurs, and the moment when the bridge arm voltage is equal to the negative value of the total capacitor Thevenin equivalent voltage is found as the interpolation moment, and the working state of all sub-modules of the corresponding bridge arm is adjusted to reverse bypass according to the interpolation moment.

7. A hybrid MMC transient simulation device based on blocking mode interpolation, characterized in that: It includes a data acquisition calculation module, a prediction calculation module, a conversion calculation module and an interpolation execution module; The data acquisition calculation module is used to obtain the total submodule voltage of each bridge arm and the Thevenin equivalent voltage history of each submodule capacitor in the previous time step when the hybrid MMC electromagnetic transient model is in the locking mode; according to the Thevenin equivalent voltage history of all submodule capacitors, the total capacitance Thevenin equivalent voltage of all submodules in the previous time step is calculated; The pre-judgment calculation module is used to obtain the pre-judgment locking working mode of all sub-modules according to the comparison of the total capacitor Thevenin equivalent voltage and the total sub-module voltage; obtain the parameter data of each bridge arm of the hybrid MMC, and calculate according to the pre-judgment locking working mode and the parameter data to obtain the Thevenin equivalent resistance of the corresponding bridge arm; The conversion calculation module is used to convert the equivalent voltage source of the hybrid MMC and the Thevenin equivalent resistance of all bridge arms to obtain the Norton circuit of the hybrid MMC; and calculate the bridge arm voltage of each bridge arm at the current time step according to the Norton circuit; The interpolation execution module is used to judge whether the predicted locking working mode of the corresponding bridge arm is predicted correctly according to the bridge arm voltage of the bridge arm and the total capacitance Thevenin equivalent voltage; if the prediction is wrong, find the interpolation time and adjust the working state of all submodules of the corresponding bridge arm according to the interpolation time; The parameter data includes the number of half-bridge sub-modules, the number of full-bridge sub-modules, on-resistance, off-resistance and equivalent resistance of sub-module capacitance of the bridge arm.

8. The hybrid MMC transient simulation device based on blocking mode interpolation according to claim 7, characterized in that: The pre-judgment calculation module includes a pre-judgment submodule and an equivalent resistance calculation submodule; The prejudgment submodule is used to, according to the total submodule voltage being greater than the total capacitor Thevenin equivalent voltage, the prejudgment locking working mode of all submodules is a forward charging working mode; according to the total submodule voltage being less than the negative value of the total capacitor Thevenin equivalent voltage, the prejudgment locking working mode of all submodules is a reverse bypass working mode; according to the total submodule voltage being not less than the negative value of the total capacitor Thevenin equivalent voltage and the total submodule voltage being not greater than the total capacitor Thevenin equivalent voltage, the prejudgment locking working mode of all submodules is a cutoff working mode; The equivalent resistance calculation submodule is used to calculate the Thevenin equivalent resistance of the corresponding bridge arm according to the first equivalent resistance calculation formula according to the parameter data based on the predicted locking working mode of all submodules being the forward charging working mode; to calculate the Thevenin equivalent resistance of the corresponding bridge arm according to the second equivalent resistance calculation formula according to the parameter data based on the predicted locking working mode of all submodules being the reverse bypass working mode; to calculate the Thevenin equivalent resistance of the corresponding bridge arm according to the third equivalent resistance calculation formula according to the parameter data based on the predicted locking working mode of all submodules being the cutoff working mode; Wherein, the first equivalent resistance calculation formula is: The second equivalent resistance calculation formula is: The third equivalent resistance calculation formula: In the formula, R smtoteq is the Thevenin equivalent resistance of the bridge arm, N h is the number of half-bridge submodules in the bridge arm, N f is the number of full-bridge submodules in the bridge arm, R on is the on-resistance of the bridge arm, R c is the equivalent resistance of the submodule capacitor of the bridge arm, R off is the off resistance of the bridge arm.

9. The hybrid MMC transient simulation device based on blocking mode interpolation according to claim 7, characterized in that: The interpolation execution module includes a first judgment submodule, a second judgment submodule and a third judgment submodule; The first judgment submodule is used to determine that the prejudgment locking working mode of the bridge arm is a forward charging working mode. If the bridge arm voltage is greater than the total capacitor Thevenin equivalent voltage, the prejudgment is correct; if the bridge arm voltage is less than the total capacitor Thevenin equivalent voltage, the prejudgment is wrong, and the time corresponding to the bridge arm voltage being equal to the total capacitor Thevenin equivalent voltage is found as the interpolation time. moment, and adjust the working state of all submodules of the corresponding bridge arm to be cut off according to the interpolation moment; The second judgment submodule is used to determine that the prejudgment locking working mode of the bridge arm is a reverse bypass working mode, and if the bridge arm voltage is less than the negative value of the total capacitor Thevenin equivalent voltage, the prejudgment is correct; If the bridge arm voltage is greater than the negative value of the total capacitor Thevenin equivalent voltage, it is predicted that an error occurs, and the time corresponding to the negative value of the bridge arm voltage equal to the total capacitor Thevenin equivalent voltage is found as the interpolation time, and the working state of all submodules of the corresponding bridge arm is adjusted to cutoff according to the interpolation time; The third judgment submodule is used for judging that the locking working mode of the bridge arm is the cut-off working mode according to the prediction, and if the bridge arm voltage is not less than the negative value of the total capacitor Thevenin equivalent voltage and the bridge arm voltage is not greater than the total capacitor Thevenin equivalent voltage, then the prediction is correct; If the bridge arm voltage is greater than the total capacitor Thevenin equivalent voltage, it is predicted that an error occurs, and the moment when the bridge arm voltage is equal to the total capacitor Thevenin equivalent voltage is found as the interpolation moment, and the working state of all sub-modules of the corresponding bridge arm is adjusted to forward charging according to the interpolation moment; if the bridge arm voltage is less than the negative value of the total capacitor Thevenin equivalent voltage, it is predicted that an error occurs, and the moment when the bridge arm voltage is equal to the negative value of the total capacitor Thevenin equivalent voltage is found as the interpolation moment, and the working state of all sub-modules of the corresponding bridge arm is adjusted to reverse bypass according to the interpolation moment.

10. A terminal device, characterized in that: including a processor and a memory; The memory is used to store program codes and transmit the program codes to the processor; The processor is used to execute the hybrid MMC transient simulation method based on locking mode interpolation according to any one of claims 1 to 6 according to the instructions in the program code.

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