Hybrid MMC Transient Simulation Method and Device Based on Locking Mode Interpolation

Abstract

The present application relates to a hybrid MMC transient simulation method, device and equipment based on blocked mode interpolation. The method first predicts its predicted blocking operation mode by acquiring the data of the previous time step of the transient simulation of the hybrid MMC, calculates the Thevenin equivalent resistance of the arm according to the predicted blocking operation mode, and then simulates the Norton circuit according to the Thevenin equivalent resistance of the arm to perform simulation calculations to obtain the arm voltage of the arm at the current time step, greatly reducing the number of switches and having higher simulation efficiency; Finally, verify whether the predicted blocking operation mode is correct according to the arm voltage at the current time step and the total capacitance Thevenin equivalent voltage at the previous time step, and correct the incorrect blocking operation mode to obtain more accurate simulation data of the hybrid MMC, solving the problem that in the MMC blocking mode, there is an interpolation problem in the existing simulation of the hybrid MMC, resulting in low simulation accuracy.

Description

Technical Field

[0001] The present application relates to the technical field of power system calculation and analysis, and particularly to a hybrid MMC transient simulation method, device and equipment based on blocking mode interpolation. Background Art

[0002] A hybrid modular multilevel converter (MMC) is composed of a mixture of half-bridge and full-bridge sub-modules. The hybrid modular multilevel converter takes into account both the DC fault ride-through ability and economy, and has broad application prospects. The accurate and efficient simulation of the electromagnetic transient model of the hybrid MMC is of great significance for the preliminary planning and design of DC projects, as well as for the safety and stability calculation and analysis involved in the operation and dispatching of DC projects and AC-DC large power grids containing hybrid MMCs.

[0003] At present, in actual transmission projects, hybrid MMC sub-modules are adopted. There are hundreds of sub-modules in a single arm of the hybrid MMC sub-module. Considering that a valve group consists of six arms, a station has two poles, and each pole has two valve groups (high and low), there are tens of thousands of sub-modules in a two-terminal hybrid MMC DC. The number of switches is large and the simulation time is long. At present, when using commercial software to simulate a hybrid MMC DC example composed of 20,544 sub-modules, the transient process of simulating 6 s with a simulation step of 10 us takes 78 min, which is difficult to meet the actual calculation requirements. In addition, the hybrid MMC includes two operating modes: blocking and unlocking. Among them, in the blocking mode, due to the different operating states of the hybrid MMC and the complex switching, there is an interpolation problem. How to correctly simulate the blocking mode of the hybrid MMC and achieve its accurate and efficient simulation has always been a difficult point in the electromagnetic transient simulation of the full state of the hybrid MMC. Summary of the Invention

[0004] Embodiments of the present application provide a hybrid MMC transient simulation method, device and equipment based on blocking mode interpolation, which are used to solve the technical problem that in the blocking mode of the MMC, there is an interpolation problem in the existing simulation of the hybrid MMC, resulting in low simulation accuracy.

[0005] To achieve the above object, the embodiments of the present application provide the following technical solutions:

[0006] On the one hand, a hybrid MMC transient simulation method based on blocking mode interpolation is provided, including the following steps:

[0007] Obtain the total sub-module voltage of each arm and the historical quantity of the Thevenin equivalent voltage of each sub-module capacitor at the previous time step when the electromagnetic transient model of the hybrid MMC is in the blocking mode; calculate the total capacitor Thevenin equivalent voltage of all sub-modules at the previous time step according to the historical quantity of the Thevenin equivalent voltage of all sub-module capacitors;

[0008] Compare the total capacitance Thevenin equivalent voltage with the total sub-module voltage to obtain the predicted blocking working modes of all sub-modules; obtain the parameter data of each arm of the hybrid MMC, and calculate according to the predicted blocking working modes and the parameter data to obtain the Thevenin equivalent resistance of the corresponding arm.

[0009] Convert according to the equivalent voltage source of the hybrid MMC and the Thevenin equivalent resistances of all arms to obtain the Norton circuit of the hybrid MMC; calculate the arm voltage of each arm at the current time step according to the Norton circuit.

[0010] Judge whether the predicted blocking working mode of the corresponding arm is predicted correctly according to the arm voltage of the arm and the total capacitance Thevenin equivalent voltage; if the prediction is incorrect, find the interpolation moment and adjust the working states of all sub-modules of the corresponding arm according to the interpolation moment.

[0011] Wherein, the parameter data includes the number of half-bridge sub-modules, the number of full-bridge sub-modules, the on-resistance, the off-resistance and the sub-module capacitance equivalent resistance of the arm.

[0012] Preferably, comparing the total capacitance Thevenin equivalent voltage with the total sub-module voltage to obtain the predicted blocking working modes of all sub-modules includes:

[0013] If the total sub-module voltage is greater than the total capacitance Thevenin equivalent voltage, the predicted blocking working mode of all sub-modules is the forward charging working mode.

[0014] If the total sub-module voltage is less than the negative value of the total capacitance Thevenin equivalent voltage, the predicted blocking working mode of all sub-modules is the reverse bypass working mode.

[0015] If the total sub-module voltage is not less than the negative value of the total capacitance Thevenin equivalent voltage and the total sub-module voltage is not greater than the total capacitance Thevenin equivalent voltage, the predicted blocking working mode of all sub-modules is the cut-off working mode.

[0016] Preferably, obtaining the parameter data of each arm of the hybrid MMC, and calculating according to the predicted blocking working mode and the parameter data to obtain the Thevenin equivalent resistance of the corresponding arm includes:

[0017] If the predicted blocking working mode of all sub-modules is the forward charging working mode, calculate according to the parameter data using the first equivalent resistance calculation formula to obtain the Thevenin equivalent resistance of the corresponding arm.

[0018] If the predicted blocking operating mode of all sub-modules is the reverse bypass operating mode, calculate according to the parameter data using the second equivalent resistance calculation formula to obtain the Thevenin equivalent resistance of the corresponding arm;

[0019] If the predicted blocking operating mode of all sub-modules is the cut-off operating mode, calculate according to the parameter data using the third equivalent resistance calculation formula to obtain the Thevenin equivalent resistance of the corresponding arm;

[0020] Among them, the first equivalent resistance calculation formula is:

[0021]

[0022] The second equivalent resistance calculation formula is:

[0023]

[0024] The third equivalent resistance calculation formula:

[0025]

[0026] In the formula, R smtoteq is the Thevenin equivalent resistance of the arm, N h is the number of half-bridge sub-modules of the arm, N f is the number of full-bridge sub-modules of the arm, R on is the on-resistance of the arm, R c is the equivalent resistance of the sub-module capacitor of the arm, R off is the off-resistance of the arm.

[0027] Preferably, judge whether the predicted blocking operating mode of the corresponding arm is predicted correctly according to the arm voltage of the arm and the total capacitor Thevenin equivalent voltage of the arm. If the prediction is incorrect, find the interpolation moment and adjust the operating states of all sub-modules of the corresponding arm according to the interpolation moment, including:

[0028] According to the predicted blocking operating mode of the arm being the forward charging operating mode, if the arm voltage is greater than the total capacitor Thevenin equivalent voltage of the arm, the prediction is correct;

[0029] If the arm voltage is less than the total capacitor Thevenin equivalent voltage of the arm, the prediction is incorrect. Find the moment when the arm voltage is equal to the total capacitor Thevenin equivalent voltage of the arm as the interpolation moment, and adjust the operating states of all sub-modules of the corresponding arm to cut-off according to the interpolation moment.

[0030] Preferably, judge whether the predicted blocking operating mode of the corresponding arm is predicted correctly according to the arm voltage of the arm and the total capacitor Thevenin equivalent voltage of the arm. If the prediction is incorrect, find the interpolation moment and adjust the operating states of all sub-modules of the corresponding arm according to the interpolation moment, including:

[0031] According to the predicted blocking operating mode of the arm being the reverse bypass operating mode, if the arm voltage is less than the negative value of the total capacitor Thevenin equivalent voltage, the prediction is correct;

[0032] If the arm voltage is greater than the negative value of the total capacitor Thevenin equivalent voltage, the prediction is incorrect. Find the corresponding time when the arm voltage is equal to the negative value of the total capacitor Thevenin equivalent voltage as the interpolation time, and adjust the operating states of all sub-modules of the corresponding arm to cutoff according to the interpolation time.

[0033] Preferably, to determine whether the predicted blocking operating mode of the arm is correctly predicted based on the arm voltage of the arm and the total capacitor Thevenin equivalent voltage. If the prediction is incorrect, finding the interpolation time and adjusting the operating states of all sub-modules of the corresponding arm according to the interpolation time includes:

[0034] According to the predicted blocking operating mode of the arm being the cutoff operating mode, if the arm voltage is not less than the negative value of the total capacitor Thevenin equivalent voltage and the arm voltage is not greater than the total capacitor Thevenin equivalent voltage, the prediction is correct;

[0035] If the arm voltage is greater than the total capacitor Thevenin equivalent voltage, the prediction is incorrect. Find the corresponding time when the arm voltage is equal to the total capacitor Thevenin equivalent voltage as the interpolation time, and adjust the operating states of all sub-modules of the corresponding arm to forward charge according to the interpolation time.

[0036] If the arm voltage is less than the negative value of the total capacitor Thevenin equivalent voltage, the prediction is incorrect. Find the corresponding time when the arm voltage is equal to the negative value of the total capacitor Thevenin equivalent voltage as the interpolation time, and adjust the operating states of all sub-modules of the corresponding arm to reverse bypass according to the interpolation time.

[0037] On the other hand, a hybrid MMC transient simulation device based on blocking mode interpolation is provided, including a data acquisition and calculation module, a prediction calculation module, a conversion calculation module, and an interpolation execution module;

[0038] The data acquisition and calculation module is used to obtain the historical quantities of the total sub-module voltage of each arm and the Thevenin equivalent voltage of each sub-module capacitor of the hybrid MMC electromagnetic transient model in the blocking mode at the previous time step; calculate according to the historical quantities of the Thevenin equivalent voltage of all sub-module capacitors to obtain the total capacitor Thevenin equivalent voltage of all sub-modules at the previous time step;

[0039] The prediction calculation module is used to compare the total capacitance Thevenin equivalent voltage with the total sub-module voltage to obtain the predicted blocking working modes of all sub-modules; obtain the parameter data of each arm of the hybrid MMC, and calculate according to the predicted blocking working modes and the parameter data to obtain the Thevenin equivalent resistance of the corresponding arm.

[0040] The conversion calculation module is used to perform conversion according to the equivalent voltage source of the hybrid MMC and the Thevenin equivalent resistances of all arms to obtain the Norton circuit of the hybrid MMC; calculate the arm voltage of each arm at the current time step according to the Norton circuit.

[0041] The interpolation execution module is used to determine whether the predicted blocking working mode of the corresponding arm is predicted correctly according to the arm voltage of the arm and the total capacitance Thevenin equivalent voltage; if the prediction is incorrect, find the interpolation moment and adjust the working states of all sub-modules of the corresponding arm according to the interpolation moment.

[0042] Wherein, the parameter data includes the number of half-bridge sub-modules, the number of full-bridge sub-modules, the on-resistance, the off-resistance and the sub-module capacitance equivalent resistance of the arm.

[0043] Preferably, the prediction calculation module includes a prediction sub-module and an equivalent resistance calculation sub-module;

[0044] The prediction sub-module is used to determine that if the total sub-module voltage is greater than the total capacitance Thevenin equivalent voltage, the predicted blocking working mode of all sub-modules is the forward charging working mode; if the total sub-module voltage is less than the negative value of the total capacitance Thevenin equivalent voltage, the predicted blocking working mode of all sub-modules is the reverse bypass working mode; if the total sub-module voltage is not less than the negative value of the total capacitance Thevenin equivalent voltage and the total sub-module voltage is not greater than the total capacitance Thevenin equivalent voltage, the predicted blocking working mode of all sub-modules is the cut-off working mode;

[0045] The equivalent resistance calculation sub-module is used to calculate the Thevenin equivalent resistance of the corresponding arm according to the first equivalent resistance calculation formula according to the predicted blocking working mode of all sub-modules being the forward charging working mode and the parameter data; calculate the Thevenin equivalent resistance of the corresponding arm according to the second equivalent resistance calculation formula according to the predicted blocking working mode of all sub-modules being the reverse bypass working mode and the parameter data; calculate the Thevenin equivalent resistance of the corresponding arm according to the third equivalent resistance calculation formula according to the predicted blocking working mode of all sub-modules being the cut-off working mode and the parameter data.

[0046] Wherein, the first equivalent resistance calculation formula is:

[0047]

[0048] The calculation formula for the second equivalent resistance is as follows:

[0049]

[0050] The calculation formula for the third equivalent resistance:

[0051]

[0052] In the formula, R smtoteq is the Thevenin equivalent resistance of the bridge arm, N h is the number of half-bridge sub-modules of the bridge arm, N f is the number of full-bridge sub-modules of the bridge arm, R on is the on-resistance of the bridge arm, R c is the equivalent resistance of the sub-module capacitor of the bridge arm, R off is the off-resistance of the bridge arm.

[0053] Preferably, the interpolation execution module includes a first judgment sub-module, a second judgment sub-module, and a third judgment sub-module;

[0054] The first judgment sub-module is used to determine that the predicted blocking working mode of the bridge arm is the forward charging working mode. If the voltage of the bridge arm is greater than the total equivalent Thevenin voltage of the capacitor, the prediction is correct; if the voltage of the bridge arm is less than the total equivalent Thevenin voltage of the capacitor, the prediction is incorrect. Find the corresponding time when the voltage of the bridge arm is equal to the total equivalent Thevenin voltage of the capacitor as the interpolation time, and adjust the working states of all sub-modules of the corresponding bridge arm to cut-off according to the interpolation time;

[0055] The second judgment sub-module is used to determine that the predicted blocking working mode of the bridge arm is the reverse bypass working mode. If the voltage of the bridge arm is less than the negative value of the total equivalent Thevenin voltage of the capacitor, the prediction is correct; if the voltage of the bridge arm is greater than the negative value of the total equivalent Thevenin voltage of the capacitor, the prediction is incorrect. Find the corresponding time when the voltage of the bridge arm is equal to the negative value of the total equivalent Thevenin voltage of the capacitor as the interpolation time, and adjust the working states of all sub-modules of the corresponding bridge arm to cut-off according to the interpolation time;

[0056] The third judgment sub-module is configured to determine that the predicted blocking operating mode of the arm is the cut-off operating mode. If the arm voltage is not less than the negative value of the total capacitive Thevenin equivalent voltage and the arm voltage is not greater than the total capacitive Thevenin equivalent voltage, the prediction is correct; if the arm voltage is greater than the total capacitive Thevenin equivalent voltage, the prediction is incorrect, and the moment corresponding to the arm voltage equal to the total capacitive Thevenin equivalent voltage is found as the interpolation moment, and the operating states of all sub-modules of the corresponding arm are adjusted to forward charge according to the interpolation moment; if the arm voltage is less than the negative value of the total capacitive Thevenin equivalent voltage, the prediction is incorrect, and the moment corresponding to the arm voltage equal to the negative value of the total capacitive Thevenin equivalent voltage is found as the interpolation moment, and the operating states of all sub-modules of the corresponding arm are adjusted to reverse bypass according to the interpolation moment.

[0057] On the other hand, a terminal device is provided, including a processor and a memory;

[0058] The memory is used to store program codes and transmit the program codes to the processor;

[0059] The processor is configured to execute the above-mentioned hybrid MMC transient simulation method based on blocking mode interpolation according to the instructions in the program codes.

[0060] The hybrid MMC transient simulation method, device, and equipment based on locked-mode interpolation. The method includes obtaining the total sub-module voltage of each arm and the historical quantities of the Thevenin equivalent voltages of each sub-module capacitor of the hybrid MMC electromagnetic transient model in the locked mode at the previous time step; calculating based on the historical quantities of the Thevenin equivalent voltages of all sub-module capacitors to obtain the total capacitor Thevenin equivalent voltage of all sub-modules at the previous time step; comparing the total capacitor Thevenin equivalent voltage with the total sub-module voltage to obtain the predicted locked operating mode of all sub-modules; obtaining the parameter data of each arm of the hybrid MMC, and calculating based on the predicted locked operating mode and the parameter data to obtain the Thevenin equivalent resistance of the corresponding arm; performing conversion based on the equivalent voltage source of the hybrid MMC and the Thevenin equivalent resistances of all arms to obtain the Norton circuit of the hybrid MMC; calculating the arm voltage of each arm at the current time step according to the Norton circuit; judging whether the predicted locked operating mode of the corresponding arm is correctly predicted based on the arm voltage of the arm and the total capacitor Thevenin equivalent voltage; if the prediction is incorrect, finding the interpolation moment and adjusting the operating states of all sub-modules of the corresponding arm according to the interpolation moment. From the above technical solutions, it can be seen that the embodiments of the present application have the following advantages: The hybrid MMC transient simulation method based on locked-mode interpolation first predicts its predicted locked operating 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 arm according to the predicted locked operating mode, and then simulates the Norton circuit according to the Thevenin equivalent resistance of the arm to perform simulation calculations to obtain the arm voltage of the current time step, greatly reducing the number of switches and having higher simulation efficiency; finally, verifying whether the predicted locked operating mode is correct based on the arm voltage of the current time step and the total capacitor Thevenin equivalent voltage of the previous time step, and correcting the incorrect locked operating mode to obtain more accurate simulation data of the hybrid MMC, solving the technical problem that in the locked mode of the MMC, there is an interpolation problem in the existing simulation of the hybrid MMC, resulting in low simulation accuracy. Description of the Drawings

[0061] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0062] Figure 1 It is a flowchart of the steps of the hybrid MMC transient simulation method based on locked-mode interpolation described in the embodiments of the present application;

[0063] Figure 2Topological structure diagram of the hybrid MMC in the hybrid MMC transient simulation method based on blocking mode interpolation according to the embodiments of the present application;

[0064] Figure 3 Conversion diagram of the equivalent Thevenin circuit and Norton circuit of one arm of the hybrid MMC in the hybrid MMC transient simulation method based on blocking mode interpolation according to the embodiments of the present application;

[0065] Figure 4 Equivalent model diagram of the hybrid MMC transient simulation in the hybrid MMC transient simulation method based on blocking mode interpolation according to the embodiments of the present application;

[0066] Figure 5 Frame schematic diagram of the hybrid MMC transient simulation device based on blocking mode interpolation according to the embodiments of the present application. Detailed implementation manners

[0067] To make the objectives, features, and advantages of the present application more obvious and understandable, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the embodiments described below are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0068] In the description of the embodiments of the present application, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present application, "a plurality of" means two or more unless otherwise specifically defined.

[0069] In the embodiments of the present application, unless otherwise clearly specified and defined, the terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal connection of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific situations.

[0070] The embodiment of the present application provides a hybrid MMC transient simulation method, device and equipment based on blocking mode interpolation, which solves the technical problem that in the blocking mode of MMC, there is an interpolation problem in the existing simulation of the hybrid MMC, resulting in low simulation accuracy.

[0071] Embodiment 1:

[0072] Figure 1 It is the flowchart of the steps of the hybrid MMC transient simulation method based on blocking mode interpolation described in the embodiment of the present application. Figure 2 It is the topological structure diagram of the hybrid MMC in the hybrid MMC transient simulation method described in the embodiment of the present application. In this embodiment, as Figure 2 shown, the six bridge arms of the three phases of the hybrid MMC are the same. Taking a single bridge arm as an example, the hybrid MMC transient simulation method based on blocking mode interpolation is described.

[0073] As Figure 1 shown, the embodiment of the present application provides a hybrid MMC transient simulation method based on blocking mode interpolation, including the following steps:

[0074] S1. Obtain the total sub-module voltage of each bridge arm and the historical quantity of the Thevenin equivalent voltage of each sub-module capacitor at the previous time step when the hybrid MMC electromagnetic transient model is in the blocking mode; calculate according to the historical quantity of the Thevenin equivalent voltage of all sub-module capacitors to obtain the total capacitor Thevenin equivalent voltage of all sub-modules at the previous time step.

[0075] It should be noted that in step S1, first, the total sub-module voltage u smtot (t - Δt) of each bridge arm and the historical quantity of the Thevenin equivalent voltage u ceqi (t - Δt) of each sub-module capacitor when the hybrid MMC electromagnetic transient model is in the blocking mode at the previous time step; secondly, according to the historical quantity of the Thevenin equivalent voltage u ceqi (t - Δt) of all sub-module capacitors, the total capacitor Thevenin equivalent voltage u totceq (t - Δt) of all sub-modules at the previous time step is obtained by summation calculation. Δt is the simulation step length, and t is the simulation time step. In this embodiment, when the hybrid MMC is in the blocking mode. Since in the blocking mode, whether it is a full-bridge sub-module or a half-bridge sub-module of the hybrid MMC, the currents of all sub-modules are the same, so all sub-modules in the same bridge arm have the same blocking working mode, and the blocking working modes include forward charging, reverse bypass and cut-off. First, obtain the total sub-module voltage u smtot (t - Δt) of each bridge arm at the previous time step and the historical quantity of the Thevenin equivalent voltage u ceqi(t - Δt). If all sub - modules of the hybrid MMC are in the forward charging state, calculate the value of the total capacitance Thevenin equivalent voltage of all sub - modules at the previous time step, u totceq (t - Δt), that is:

[0076]

[0077] In the formula, N is the total number of sub - modules of the arm.

[0078] S2. Compare the total capacitance Thevenin equivalent voltage with the total sub - module voltage to obtain the predicted blocking working mode of all sub - modules; obtain the parameter data of each arm of the hybrid MMC, and calculate according to the predicted blocking working mode and parameter data to obtain the Thevenin equivalent resistance of the corresponding arm. Among them, the parameter data includes the number of half - bridge sub - modules, the number of full - bridge sub - modules, the on - resistance, the off - resistance and the sub - module capacitance equivalent resistance of the arm.

[0079] It should be noted that in step S2, it is based on u totceq (t - Δt) obtained in step S1 and u smtot (t - Δt) for comparison to predict the blocking working mode of all sub - modules, and then calculate the Thevenin equivalent resistance of the corresponding arm according to the corresponding predicted blocking working mode and parameter data, so that the Thevenin equivalent resistances R smtoteq of the 6 arms in the hybrid MMC can be obtained.

[0080] Figure 3 is the conversion diagram between the equivalent Thevenin circuit and Norton circuit of one arm of the hybrid MMC in the transient simulation method of the hybrid MMC based on blocking mode interpolation of this application embodiment.

[0081] S3. Perform conversion according to the equivalent voltage source of the hybrid MMC and the Thevenin equivalent resistances of all arms to obtain the Norton circuit of the hybrid MMC; calculate the arm voltage of each arm at the current time step according to the Norton circuit.

[0082] It should be noted that in the blocking mode, whether it is the full - bridge sub - module or the half - bridge sub - module of the hybrid MMC, the currents of all sub - modules are the same. Therefore, all sub - modules in the same arm have the same blocking working mode. Thus, as Figure 3 shown, convert the equivalent voltage source U S of one arm in the hybrid MMC and the corresponding Thevenin equivalent resistance R to obtain an equivalent current I S and an equivalent output resistance G to form the Norton circuit of the hybrid MMC. Then, in the Norton circuit, the arm voltage of this arm is I S×G. In this embodiment, in the process of converting the Thévenin circuit of the hybrid MMC into a Norton circuit by the hybrid MMC transient simulation method based on blocking mode interpolation, the Norton circuit is a circuit in which the arm inductor of the hybrid MMC is equivalent to a parallel circuit of a resistor and a historical current source through the implicit trapezoidal integration method.

[0083] S4. Determine whether the predicted blocking working mode of the corresponding arm is predicted correctly according to the arm voltage of the arm and the total capacitance Thévenin equivalent voltage; if the prediction is incorrect, find the interpolation moment and adjust the working states of all sub-modules of the corresponding arm according to the interpolation moment.

[0084] It should be noted that in step S4, by comparing the arm voltage of the current time step with the total capacitance Thévenin equivalent voltage, it is determined whether the predicted blocking working mode of all sub-modules is correct. If the prediction is correct, the simulation calculation of the next time step is carried out; if the prediction is incorrect, the correct blocking working mode needs to be obtained according to the arm voltage of the current time step and the total capacitance Thévenin equivalent voltage of all sub-module capacitors, and the moment of the change of the working mode is interpolated and the working states of all sub-modules of the arm are adjusted. Among them, the working states include forward charging, reverse bypass, and cut-off.

[0085] In the embodiment of the present application, the hybrid MMC transient simulation method based on blocking mode interpolation can use a variable resistor to simulate different blocking working modes of the hybrid MMC, and only one variable resistor is used in one arm, considering both half-bridge sub-modules and full-bridge sub-modules. Compared with the existing method of considering interpolation by adding diodes or virtual diodes in the Thévenin circuit, the hybrid MMC transient simulation method based on blocking mode interpolation greatly reduces the number of switches, has higher simulation efficiency while achieving the same simulation accuracy, and the program implementation is simple and easy to implement. Without loss of simulation accuracy, the hybrid MMC transient simulation method based on blocking mode interpolation has fast calculation efficiency and simple program implementation, and is very suitable for the development of the MMC electromagnetic transient model for engineering actual calculation.

[0086] A hybrid MMC transient simulation method based on blocking mode interpolation provided by this application. The method includes obtaining the total sub-module voltage of each arm and the historical quantity of the Thevenin equivalent voltage of each sub-module capacitor of the hybrid MMC electromagnetic transient model in the blocking mode at the previous time step; calculating according to the historical quantity of the Thevenin equivalent voltage of all sub-module capacitors to obtain the total capacitor Thevenin equivalent voltage of all sub-module capacitors at the previous time step; comparing the total capacitor Thevenin equivalent voltage with the total sub-module voltage to obtain the predicted blocking working mode of all sub-module capacitors; obtaining the parameter data of each arm of the hybrid MMC, and calculating according to the predicted blocking working mode and the parameter data to obtain the Thevenin equivalent resistance of the corresponding arm; performing conversion according to the equivalent voltage source of the hybrid MMC and the Thevenin equivalent resistance of all arms to obtain the Norton circuit of the hybrid MMC; calculating the arm voltage of each arm at the current time step according to the Norton circuit; judging whether the predicted blocking working mode of the corresponding arm is predicted correctly according to the arm voltage of the arm and the total capacitor Thevenin equivalent voltage; if the prediction is incorrect, find the interpolation moment and adjust the working state of all sub-modules of the corresponding arm according to the interpolation moment. The hybrid MMC transient simulation method based on blocking mode interpolation first predicts its predicted blocking working mode by obtaining the data of the previous time step of the hybrid MMC transient simulation, calculates the Thevenin equivalent resistance of the arm according to the predicted blocking working mode, and then simulates the Norton circuit according to the Thevenin equivalent resistance of the arm to perform simulation calculation to obtain the arm voltage of the current time step, which greatly reduces the number of switches and has higher simulation efficiency; finally, verify whether the predicted blocking working mode is correct according to the arm voltage of the current time step and the total capacitor Thevenin equivalent voltage of the previous time step, and correct the incorrect blocking working mode to obtain more accurate simulation data of the hybrid MMC, solving the technical problem that in the blocking mode of the MMC, there is an interpolation problem in the existing simulation of the hybrid MMC, resulting in low simulation accuracy.

[0087] Figure 4 It is the equivalent model diagram of the hybrid MMC transient simulation in the hybrid MMC transient simulation method based on blocking mode interpolation described in the embodiment of this application.

[0088] In an embodiment of this application, comparing the total capacitor Thevenin equivalent voltage with the total sub-module voltage to obtain the predicted blocking working mode of all sub-module capacitors includes:

[0089] If the total sub-module voltage is greater than the total capacitor Thevenin equivalent voltage, the predicted blocking working mode of all sub-module capacitors is the forward charging working mode;

[0090] If the total sub-module voltage is less than the negative value of the total capacitor Thevenin equivalent voltage, the predicted blocking working mode of all sub-module capacitors is the reverse bypass working mode;

[0091] If the total sub-module voltage is not less than the negative value of the total capacitor Thevenin equivalent voltage and the total sub-module voltage is not greater than the total capacitor Thevenin equivalent voltage, the predicted blocking operating mode of all sub-modules is the cut-off operating mode.

[0092] It should be noted that, as Figure 4 shown, this hybrid MMC transient simulation method based on blocking mode interpolation predicts the blocking operating mode of all sub-modules according to the total sub-module voltage of each arm and the total capacitor Thevenin equivalent voltage of all sub-modules, and records it as the predicted blocking operating mode, and then calculates the Thevenin equivalent resistance of all sub-modules of the entire arm.

[0093] In the embodiment of the present application, obtaining the parameter data of each arm of the hybrid MMC and calculating according to the predicted blocking operating mode and the parameter data to obtain the Thevenin equivalent resistance of the corresponding arm includes:

[0094] If the predicted blocking operating mode of all sub-modules is the forward charging operating mode, calculate according to the parameter data using the first equivalent resistance calculation formula to obtain the Thevenin equivalent resistance of the corresponding arm;

[0095] If the predicted blocking operating mode of all sub-modules is the reverse bypass operating mode, calculate according to the parameter data using the second equivalent resistance calculation formula to obtain the Thevenin equivalent resistance of the corresponding arm;

[0096] If the predicted blocking operating mode of all sub-modules is the cut-off operating mode, calculate according to the parameter data using the third equivalent resistance calculation formula to obtain the Thevenin equivalent resistance of the corresponding arm;

[0097] Among them, the first equivalent resistance calculation formula is:

[0098]

[0099] The second equivalent resistance calculation formula is:

[0100]

[0101] The third equivalent resistance calculation formula:

[0102]

[0103] In the formula, R smtoteq is the Thevenin equivalent resistance of the arm, N h is the number of half-bridge sub-modules of the arm, N f is the number of full-bridge sub-modules of the arm, R on is the on-resistance of the arm, R c is the equivalent resistance of the sub-module capacitor of the arm, R off is the off-resistance of the arm.

[0104] It should be noted that when u smtot (t - Δt) > u totceq (t - Δt), it is determined that the predicted blocking working mode of all sub - modules is the forward charging working mode, and the Thevenin equivalent resistance of the corresponding arm is calculated using the first equivalent resistance calculation formula; when u smtot (t - Δt) < -u totceq (t - Δt), it is determined that the predicted blocking working mode of all sub - modules is the reverse bypass working mode, and the Thevenin equivalent resistance of the corresponding arm is calculated using the second equivalent resistance calculation formula; when -u totceq (t - Δt) ≤ u smtot (t) ≤ u totceq (t - Δt), it is determined that the predicted blocking working mode of all sub - modules is the cut - off working mode, and the Thevenin equivalent resistance of the corresponding arm is calculated using the third equivalent resistance calculation formula.

[0105] In an embodiment of the present application, it is determined whether the predicted blocking working mode of the corresponding arm is predicted correctly according to the arm voltage of the arm and the total capacitive Thevenin equivalent voltage. If the prediction is incorrect, the interpolation time is found and the working states of all sub - modules of the corresponding arm are adjusted according to the interpolation time, including:

[0106] According to the predicted blocking working mode of the arm being the forward charging working mode, if the arm voltage is greater than the total capacitive Thevenin equivalent voltage, the prediction is correct; if the arm voltage is less than the total capacitive Thevenin equivalent voltage, the prediction is incorrect, and the time corresponding to the arm voltage equal to the total capacitive Thevenin equivalent voltage is found as the interpolation time, and the working states of all sub - modules of the corresponding arm are adjusted to cut - off according to the interpolation time;

[0107] According to the predicted blocking working mode of the arm being the reverse bypass working mode, if the arm voltage is less than the negative value of the total capacitive Thevenin equivalent voltage, the prediction is correct; if the arm voltage is greater than the negative value of the total capacitive Thevenin equivalent voltage, the prediction is incorrect, and the time corresponding to the arm voltage equal to the negative value of the total capacitive Thevenin equivalent voltage is found as the interpolation time, and the working states of all sub - modules of the corresponding arm are adjusted to cut - off according to the interpolation time;

[0108] According to the predicted blocking operating mode of the arm being the cut-off operating mode, if the arm voltage is not less than the negative value of the total capacitive Thevenin equivalent voltage and the arm voltage is not greater than the total capacitive Thevenin equivalent voltage, the prediction is correct; if the arm voltage is greater than the total capacitive Thevenin equivalent voltage, the prediction is incorrect, find the moment when the arm voltage is equal to the total capacitive Thevenin equivalent voltage as the interpolation moment, and adjust the operating states of all sub-modules of the corresponding arm to forward charging according to the interpolation moment; if the arm voltage is less than the negative value of the total capacitive Thevenin equivalent voltage, the prediction is incorrect, find the moment when the arm voltage is equal to the negative value of the total capacitive Thevenin equivalent voltage as the interpolation moment, and adjust the operating states of all sub-modules of the corresponding arm to reverse bypass according to the interpolation moment.

[0109] It should be noted that, as Figure 4 shown, this hybrid MMC transient simulation method based on interpolation of the blocking mode determines whether the predicted blocking operating mode of each arm is correct and whether interpolation is required according to the arm voltage u smtot (t) at the current time step. In this embodiment, the predicted blocking operating modes are judged separately. According to the predicted blocking operating mode of the arm being the forward charging operating mode, when u smtot (t)>u totceq (t - Δt), the predicted blocking operating mode is correct, and the next step of the hybrid MMC transient simulation calculation is carried out; when u smtot (t)<u totceq (t - Δt), the predicted blocking operating mode is incorrect, interpolate to find the interpolation moment t0 corresponding to u smtot (t) = u totceq (t - Δt), and adjust the operating states of all sub-modules of the arm to cut-off at the interpolation moment t0. According to the predicted blocking operating mode of the arm being the reverse bypass operating mode, when u smtot (t)<-u totceq (t - Δt), the predicted blocking operating mode is correct, and the next step of the hybrid MMC transient simulation calculation is carried out; when u smtot (t)>-u totceq (t - Δt), the predicted blocking operating mode is incorrect, find the interpolation moment t0 corresponding to u smtot (t) = -u totceq (t - Δt), and adjust the operating states of all sub-modules of the arm to cut-off at the interpolation moment t0. According to the predicted blocking operating mode of the arm being the cut-off operating mode, when -u totceq (t - Δt) ≤ u smtot (t) ≤ u totceq (t - Δt), the predicted blocking operating mode is correct, and the next step of the hybrid MMC transient simulation calculation is carried out; when u smtot(t) > u totceq If it is at (t - Δt), the predicted blocking operation mode is incorrect, and search for u smtot (t) = u totceq At the interpolation time t0 corresponding to (t - Δt), adjust the operating states of all sub-modules of the arm to forward charging at the interpolation time t0. When u smtot (t) < -u totceq If it is at (t - Δt), the predicted blocking operation mode is incorrect, and search for u smtot (t) = -u totceq At the interpolation time t0 corresponding to (t - Δt), adjust the operating states of all sub-modules of the arm to reverse bypass at the interpolation time t0.

[0110] Embodiment 2:

[0111] Figure 5 It is a framework schematic diagram of the hybrid MMC transient simulation device based on blocking mode interpolation according to the embodiment of the present application.

[0112] As Figure 5 shown, the embodiment of the present application provides a hybrid MMC transient simulation device based on blocking mode interpolation, including a data acquisition and calculation module 10, a prediction calculation module 20, a conversion calculation module 30, and an interpolation execution module 40;

[0113] The data acquisition and calculation module 10 is used to obtain the total sub-module voltage of each arm and the historical quantities of the Thevenin equivalent voltages of each sub-module capacitor of the hybrid MMC electromagnetic transient model in the blocking mode; calculate according to the historical quantities of the Thevenin equivalent voltages of all sub-module capacitors to obtain the total capacitor Thevenin equivalent voltage of all sub-modules in the previous time step;

[0114] The prediction calculation module 20 is used to compare the total capacitor Thevenin equivalent voltage with the total sub-module voltage to obtain the predicted blocking operation mode of all sub-modules; obtain the parameter data of each arm of the hybrid MMC, and calculate according to the predicted blocking operation mode and the parameter data to obtain the Thevenin equivalent resistance of the corresponding arm;

[0115] The conversion calculation module 30 is used to perform conversion according to the equivalent voltage source of the hybrid MMC and the Thevenin equivalent resistances of all arms to obtain the Norton circuit of the hybrid MMC; calculate the arm voltage of each arm at the current time step according to the Norton circuit;

[0116] The interpolation execution module 40 is used to judge whether the predicted blocking operation mode of the corresponding arm is correctly predicted according to the arm voltage and the total capacitor Thevenin equivalent voltage of the arm; if the prediction is incorrect, search for the interpolation time and adjust the operating states of all sub-modules of the corresponding arm according to the interpolation time;

[0117] Among them, the parameter data includes the number of half-bridge sub-modules, the number of full-bridge sub-modules, the on-resistance, the off-resistance, and the equivalent resistance of the sub-module capacitor in the bridge arm.

[0118] In the embodiment of the present application, the pre-judgment calculation module 20 includes a pre-judgment sub-module and an equivalent resistance calculation sub-module;

[0119] The pre-judgment sub-module is configured to determine that the pre-judgment blocking working mode of all sub-modules is the forward charging working mode if the total sub-module voltage is greater than the total capacitor Thevenin equivalent voltage; determine that the pre-judgment blocking working mode of all sub-modules is the reverse bypass working mode if the total sub-module voltage is less than the negative value of the total capacitor Thevenin equivalent voltage; determine that the pre-judgment blocking working mode of all sub-modules is the cut-off working mode if the total sub-module voltage is not less than the negative value of the total capacitor Thevenin equivalent voltage and the total sub-module voltage is not greater than the total capacitor Thevenin equivalent voltage;

[0120] The equivalent resistance calculation sub-module is configured to calculate the Thevenin equivalent resistance of the corresponding bridge arm using the first equivalent resistance calculation formula according to the parameter data if the pre-judgment blocking working mode of all sub-modules is the forward charging working mode; calculate the Thevenin equivalent resistance of the corresponding bridge arm using the second equivalent resistance calculation formula according to the parameter data if the pre-judgment blocking working mode of all sub-modules is the reverse bypass working mode; calculate the Thevenin equivalent resistance of the corresponding bridge arm using the third equivalent resistance calculation formula according to the parameter data if the pre-judgment blocking working mode of all sub-modules is the cut-off working mode;

[0121] Among them, the first equivalent resistance calculation formula is:

[0122]

[0123] The second equivalent resistance calculation formula is:

[0124]

[0125] The third equivalent resistance calculation formula:

[0126]

[0127] In the formula, R smtoteq is the Thevenin equivalent resistance of the bridge arm, N h is the number of half-bridge sub-modules in the bridge arm, N f is the number of full-bridge sub-modules in the bridge arm, R on is the on-resistance of the bridge arm, R c is the equivalent resistance of the sub-module capacitor in the bridge arm, R off is the off-resistance of the bridge arm.

[0128] In the embodiment of the present application, the interpolation execution module 30 includes a first judgment sub-module, a second judgment sub-module, and a third judgment sub-module;

[0129] The first judgment sub-module is configured to, according to the predicted blocking operating mode of the arm being the forward charging operating mode, if the arm voltage is greater than the total capacitance Thevenin equivalent voltage, the prediction is correct; if the arm voltage is less than the total capacitance Thevenin equivalent voltage, the prediction is incorrect, find the moment when the arm voltage is equal to the total capacitance Thevenin equivalent voltage as the interpolation moment, and adjust the operating states of all sub-modules of the corresponding arm to cutoff according to the interpolation moment;

[0130] The second judgment sub-module is configured to, according to the predicted blocking operating mode of the arm being the reverse bypass operating mode, if the arm voltage is less than the negative value of the total capacitance Thevenin equivalent voltage, the prediction is correct; if the arm voltage is greater than the negative value of the total capacitance Thevenin equivalent voltage, the prediction is incorrect, find the moment when the arm voltage is equal to the negative value of the total capacitance Thevenin equivalent voltage as the interpolation moment, and adjust the operating states of all sub-modules of the corresponding arm to cutoff according to the interpolation moment;

[0131] The third judgment sub-module is configured to, according to the predicted blocking operating mode of the arm being the cutoff operating mode, if the arm voltage is not less than the negative value of the total capacitance Thevenin equivalent voltage and the arm voltage is not greater than the total capacitance Thevenin equivalent voltage, the prediction is correct; if the arm voltage is greater than the total capacitance Thevenin equivalent voltage, the prediction is incorrect, find the moment when the arm voltage is equal to the total capacitance Thevenin equivalent voltage as the interpolation moment, and adjust the operating states of all sub-modules of the corresponding arm to forward charging according to the interpolation moment; if the arm voltage is less than the negative value of the total capacitance Thevenin equivalent voltage, the prediction is incorrect, find the moment when the arm voltage is equal to the negative value of the total capacitance Thevenin equivalent voltage as the interpolation moment, and adjust the operating states of all sub-modules of the corresponding arm to reverse bypass.

[0132] It should be noted that the content of the module in the device of the second embodiment corresponds to the step content of the method in the first embodiment. The content of the hybrid MMC transient simulation method based on blocking mode interpolation has been described in the first embodiment, and the step content of the hybrid MMC transient simulation method based on blocking mode interpolation will not be described in detail in this embodiment.

[0133] Embodiment Three:

[0134] The embodiment of the present application provides a terminal device, including a processor and a memory;

[0135] The memory is used to store program code and transmit the program code to the processor;

[0136] A processor for performing the above-mentioned hybrid MMC transient simulation method based on latching mode interpolation according to the instructions in the program code.

[0137] It should be noted that the processor is used to execute the steps in the above-mentioned embodiment of the electromagnetic transient simulation fast startup method of a modular multilevel converter according to the instructions in the program code. Alternatively, when the processor executes the computer program, it realizes the functions of each module / unit in the above-mentioned system / device embodiments.

[0138] Exemplarily, the computer program can be divided into one or more modules / units, and one or more modules / units are stored in the memory and executed by the processor to complete the present application. One or more modules / units can 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 the terminal device.

[0139] The terminal device can be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The terminal device may include, but is not limited to, a processor and a memory. Those skilled in the art can understand that it does not constitute a limitation on the terminal device, and it may include more or fewer components than shown in the figure, or combine some components, or different components. For example, the terminal device may also include input / output devices, network access devices, buses, etc.

[0140] The so-called processor may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0141] The memory can be an internal storage unit of the terminal device, such as the hard disk 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 disk equipped on the terminal device, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. Further, the memory can also include both the internal storage unit of the terminal device and the external storage device. The memory is used to store computer programs as well as other programs and data required by the terminal device. The memory can also be used to temporarily store the data that has been output or will be output.

[0142] Those skilled in the art can 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 foregoing method embodiments and will not be elaborated herein.

[0143] In several embodiments provided in the present 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 illustrative. For example, the division of the units is only a logical function division, and there can be other division methods in actual implementation. For example, 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 displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces, and the indirect couplings or communication connections of the devices or units can be in electrical, mechanical, or other forms.

[0144] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0145] In addition, each functional unit in various embodiments of the present application can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0146] When 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 this application, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of this application. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs.

[0147] As described above, the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit them; although this application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of various embodiments of this application.

Claims

1. A hybrid MMC transient simulation method based on blocked-mode interpolation, characterized in that It includes the following steps: Obtain the total sub-module voltage of each arm and the historical Thevenin equivalent voltage of each sub-module capacitor at the previous time step when the hybrid MMC electromagnetic transient model is in the locked mode; calculate based on the historical Thevenin equivalent voltage of all sub-module capacitors to obtain the total capacitor Thevenin equivalent voltage of all sub-modules at the previous time step; Compare the total capacitor Thevenin equivalent voltage with the total sub-module voltage to obtain the predicted locked operating mode of all sub-modules; obtain the parameter data of each arm of the hybrid MMC, and calculate based on the predicted locked operating mode and the parameter data to obtain the Thevenin equivalent resistance of the corresponding arm; Perform conversion based on the equivalent voltage source of the hybrid MMC and the Thevenin equivalent resistance of all arms to obtain the Norton circuit of the hybrid MMC; calculate the arm voltage of each arm at the current time step according to the Norton circuit; Judge whether the predicted locked operating mode of the corresponding arm is correctly predicted based on the arm voltage of the arm and the total capacitor Thevenin equivalent voltage; if the prediction is incorrect, find the interpolation moment and adjust the operating states of all sub-modules of the corresponding arm according to the interpolation moment; Wherein, the parameter data includes the number of half-bridge sub-modules, the number of full-bridge sub-modules, the on-resistance, the off-resistance and the sub-module capacitor equivalent resistance of the arm.

2. The hybrid MMC transient simulation method based on locked-mode interpolation according to claim 1, wherein Comparing the total capacitor Thevenin equivalent voltage with the total sub-module voltage to obtain the predicted locked operating mode of all sub-modules includes: If the total sub-module voltage is greater than the total capacitor Thevenin equivalent voltage, the predicted locked operating mode of all sub-modules is the forward charging operating mode; If the total sub-module voltage is less than the negative value of the total capacitor Thevenin equivalent voltage, the predicted locked operating mode of all sub-modules is the reverse bypass operating mode; If the total sub-module voltage is not less than the negative value of the total capacitor Thevenin equivalent voltage and the total sub-module voltage is not greater than the total capacitor Thevenin equivalent voltage, the predicted locked operating mode of all sub-modules is the cut-off operating mode.

3. The hybrid MMC transient simulation method based on locked-mode interpolation according to claim 2, wherein, Obtain the parameter data of each arm of the hybrid MMC, and calculate based on the predicted locked operating mode and the parameter data to obtain the Thevenin equivalent resistance of the corresponding arm includes: If the predicted locked operating mode of all sub-modules is the forward charging operating mode, calculate according to the parameter data using the first equivalent resistance calculation formula to obtain the Thevenin equivalent resistance of the corresponding arm; If the predicted locked operating mode of all sub-modules is the reverse bypass operating mode, calculate according to the parameter data using the second equivalent resistance calculation formula to obtain the Thevenin equivalent resistance of the corresponding arm; If the predicted locked operating mode of all sub-modules is the cut-off operating mode, calculate according to the parameter data using the third equivalent resistance calculation formula to obtain the Thevenin equivalent resistance of the corresponding arm; Wherein, the first equivalent resistance calculation formula is: The second equivalent resistance calculation formula is: The third equivalent resistance calculation formula: where, R smtoteq is the Thevenin equivalent resistance of the bridge arm, N h is the number of half-bridge sub-modules of the bridge arm, N f is the number of full-bridge sub-modules of the bridge arm, R on is the on-resistance of the bridge arm, R c is the equivalent resistance of the sub-module capacitor of the bridge arm, R off is the off-resistance of the bridge arm.

4. The hybrid MMC transient simulation method based on blocked-mode interpolation according to claim 1, wherein Judge whether the predicted blocking working mode of the corresponding arm is predicted correctly according to the arm voltage of the arm and the total capacitive Thevenin equivalent voltage. If the prediction is incorrect, find the interpolation moment and adjust the working states of all sub-modules of the corresponding arm according to the interpolation moment, including: If the predicted blocking working mode of the arm is the forward charging working mode, if the arm voltage is greater than the total capacitive Thevenin equivalent voltage, the prediction is correct; If the arm voltage is less than the total capacitive Thevenin equivalent voltage, the prediction is incorrect. Find the moment when the arm voltage is equal to the total capacitive Thevenin equivalent voltage as the interpolation moment, and adjust the working states of all sub-modules of the corresponding arm to cutoff according to the interpolation moment.

5. The hybrid MMC transient simulation method based on blocked-mode interpolation according to claim 1, wherein Judge whether the predicted blocking working mode of the corresponding arm is predicted correctly according to the arm voltage of the arm and the total capacitive Thevenin equivalent voltage. If the prediction is incorrect, find the interpolation moment and adjust the working states of all sub-modules of the corresponding arm according to the interpolation moment, including: If the predicted blocking working mode of the arm is the reverse bypass working mode, if the arm voltage is less than the negative value of the total capacitive Thevenin equivalent voltage, the prediction is correct; If the arm voltage is greater than the negative value of the total capacitive Thevenin equivalent voltage, the prediction is incorrect. Find the moment when the arm voltage is equal to the negative value of the total capacitive Thevenin equivalent voltage as the interpolation moment, and adjust the working states of all sub-modules of the corresponding arm to cutoff according to the interpolation moment.

6. The hybrid MMC transient simulation method based on blocked-mode interpolation according to claim 1, characterized in that Judge whether the predicted blocking working mode of the corresponding arm is predicted correctly according to the arm voltage of the arm and the total capacitive Thevenin equivalent voltage. If the prediction is incorrect, find the interpolation moment and adjust the working states of all sub-modules of the corresponding arm according to the interpolation moment, including: If the predicted blocking working mode of the arm is the cutoff working mode, if the arm voltage is not less than the negative value of the total capacitive Thevenin equivalent voltage and the arm voltage is not greater than the total capacitive Thevenin equivalent voltage, the prediction is correct; If the arm voltage is greater than the total capacitive Thevenin equivalent voltage, the prediction is incorrect. Find the moment when the arm voltage is equal to the total capacitive Thevenin equivalent voltage as the interpolation moment, and adjust the working states of all sub-modules of the corresponding arm to forward charging; If the arm voltage is less than the negative value of the total capacitive Thevenin equivalent voltage, the prediction is incorrect. Find the moment when the arm voltage is equal to the negative value of the total capacitive Thevenin equivalent voltage as the interpolation moment, and adjust the working states of all sub-modules of the corresponding arm to reverse bypass.

7. A hybrid MMC transient simulation device based on locked mode interpolation, characterized in that, Including a data acquisition and calculation module, a prediction calculation module, a conversion calculation module and an interpolation execution module; The data acquisition and calculation module is used to obtain the historical quantities of the total sub-module voltage of each arm and the Thevenin equivalent voltage of each sub-module capacitor of the hybrid MMC electromagnetic transient model in the blocking mode at the previous time step; calculate according to the historical quantities of the Thevenin equivalent voltage of all sub-module capacitors to obtain the total capacitive Thevenin equivalent voltage of all sub-modules at the previous time step; The prediction calculation module is used to compare the total capacitance Thevenin equivalent voltage with the total sub-module voltage to obtain the predicted blocking working modes of all sub-modules; obtain the parameter data of each arm of the hybrid MMC, and calculate according to the predicted blocking working modes and the parameter data to obtain the Thevenin equivalent resistance of the corresponding arm. The conversion calculation module is used to perform conversion based on the equivalent voltage source of the hybrid MMC and the Thevenin equivalent resistances of all arms to obtain the Norton circuit of the hybrid MMC; calculate the arm voltage of each arm at the current time step according to the Norton circuit. The interpolation execution module is used to judge whether the predicted blocking working mode of the corresponding arm is predicted correctly according to the arm voltage of the arm and the total capacitance Thevenin equivalent voltage; if the prediction is incorrect, find the interpolation moment and adjust the working states of all sub-modules of the corresponding arm according to the interpolation moment. Among them, the parameter data includes the number of half-bridge sub-modules, the number of full-bridge sub-modules, the on-resistance, the off-resistance, and the sub-module capacitance equivalent resistance of the arm.

8. The hybrid MMC transient simulation device based on blocking mode interpolation according to claim 7, wherein The prediction calculation module includes a prediction sub-module and an equivalent resistance calculation sub-module. The prediction sub-module is used to determine that if the total sub-module voltage is greater than the total capacitance Thevenin equivalent voltage, the predicted blocking working mode of all sub-modules is the forward charging working mode; if the total sub-module voltage is less than the negative value of the total capacitance Thevenin equivalent voltage, the predicted blocking working mode of all sub-modules is the reverse bypass working mode; if the total sub-module voltage is not less than the negative value of the total capacitance Thevenin equivalent voltage and the total sub-module voltage is not greater than the total capacitance Thevenin equivalent voltage, the predicted blocking working mode of all sub-modules is the cut-off working mode. The equivalent resistance calculation sub-module is used to calculate the Thevenin equivalent resistance of the corresponding arm according to the predicted blocking working mode of all sub-modules being the forward charging working mode and using the first equivalent resistance calculation formula according to the parameter data; calculate the Thevenin equivalent resistance of the corresponding arm according to the predicted blocking working mode of all sub-modules being the reverse bypass working mode and using the second equivalent resistance calculation formula according to the parameter data; calculate the Thevenin equivalent resistance of the corresponding arm according to the predicted blocking working mode of all sub-modules being the cut-off working mode and using the third equivalent resistance calculation formula according to the parameter data. Among them, the first equivalent resistance calculation formula is: The second equivalent resistance calculation formula is: The third equivalent resistance calculation formula: Wherein, R smtoteq is the Thevenin equivalent resistance of the bridge arm, N h is the number of half-bridge sub-modules of the bridge arm, N f is the number of full-bridge sub-modules of the bridge arm, R on is the on-resistance of the bridge arm, R c is the equivalent resistance of the sub-module capacitor of the bridge arm, R off is the off-resistance of the bridge arm.

9. The hybrid MMC transient simulation device based on locked-mode interpolation according to claim 7, characterized in that The interpolation execution module includes a first judgment sub-module, a second judgment sub-module, and a third judgment sub-module. The first judgment sub-module is used to determine that the predicted blocking working mode of the arm is the forward charging working mode. If the arm voltage is greater than the total capacitance Thevenin equivalent voltage, the prediction is correct; if the arm voltage is less than the total capacitance Thevenin equivalent voltage, the prediction is incorrect. Find the moment when the arm voltage is equal to the total capacitance Thevenin equivalent voltage as the interpolation moment, and adjust the working states of all sub-modules of the corresponding arm to cutoff according to the interpolation moment; The second judgment sub-module is used to determine that the predicted blocking working mode of the arm is the reverse bypass working mode. If the arm voltage is less than the negative value of the total capacitance Thevenin equivalent voltage, the prediction is correct; If the arm voltage is greater than the negative value of the total capacitance Thevenin equivalent voltage, the prediction is incorrect. Find the moment when the arm voltage is equal to the negative value of the total capacitance Thevenin equivalent voltage as the interpolation moment, and adjust the working states of all sub-modules of the corresponding arm to cutoff according to the interpolation moment; The third judgment sub-module is used to determine that the predicted blocking working mode of the arm is the cutoff working mode. If the arm voltage is not less than the negative value of the total capacitance Thevenin equivalent voltage and the arm voltage is not greater than the total capacitance Thevenin equivalent voltage, the prediction is correct; If the arm voltage is greater than the total capacitance Thevenin equivalent voltage, the prediction is incorrect. Find the moment when the arm voltage is equal to the total capacitance Thevenin equivalent voltage as the interpolation moment, and adjust the working states of all sub-modules of the corresponding arm to forward charging according to the interpolation moment; if the arm voltage is less than the negative value of the total capacitance Thevenin equivalent voltage, the prediction is incorrect. Find the moment when the arm voltage is equal to the negative value of the total capacitance Thevenin equivalent voltage as the interpolation moment, and adjust the working states of all sub-modules of the corresponding arm to reverse bypass.

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

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