Full-mode equivalent modeling method for full-half hybrid modular multilevel converter

Abstract

The invention discloses a full-mode equivalent modeling method for a full-half hybrid modular multilevel converter considering a dead zone, and relates to the technical field of electric power simulation. According to the method, the influence of a switch containing dead zone control on the working state of a sub-module is fully analyzed, Thevenin equivalence based on an ideal switching device is adopted for an active switching event dominant mode, a virtual diode is introduced into a passive switching event dominant mode, all modes are connected in series through a Branch section, a full-mode equivalent model of a full-half valve section is established, and a full-mode equivalent model of the full-half valve section is established. And finally, connecting the model into a bridge arm of the modular multilevel converter in series to obtain a full-mode equivalent model of the full-semi-hybrid modular multilevel converter. The method is characterized in that the Thevenin equivalence based on the ideal switching device can greatly reduce the calculation complexity and improve the calculation efficiency on the premise that the precision is not lost; a virtual diode is introduced, and accurate positioning of a passive switching event can be realized by using an interpolation algorithm of the diode in PSCAD.

Description

Technical Field

[0001] This invention relates to a full-modal equivalent modeling method for fully-half hybrid modular multilevel converters that considers dead zones, and belongs to the field of power system simulation technology. Background Technology

[0002] Modular multilevel converters (MMCs) have been widely used in high-voltage direct current (HVDC) transmission due to their advantages such as flexible control, low harmonic content, and convenient capacity expansion. Among them, the hybrid MMC, composed of full-bridge and half-bridge submodules, combines the active fault ride-through capability of full-bridge submodules with the economic efficiency of half-bridge submodules, and has broad development prospects.

[0003] EMTDC is a fixed-time-step transient simulation program where switching states only change at integer multiples of the simulation step size. If a switching action occurs between two adjacent time steps, the actual switching action can only be detected at the next time step. In practical engineering applications, considering the switching delay of the devices themselves and the propagation delay of the drive circuit, to avoid shoot-through short-circuit faults in the complementary switching devices on the same side of the submodule, which could lead to instantaneous large currents, damage to the devices, or even system crashes, the turn-on signal needs to be delayed by a dead time. During the dead time, since both the upper and lower switching devices on the same side are off, and the inductor current cannot change abruptly, the current needs to be maintained through the freewheeling diode. At this time, the operating state of the submodule circuit is dominated by passive switching events such as diodes, whose turn-on and turn-off are determined by the voltage across the device and the current flowing through it, rather than by active switching events such as IGBTs. Passive switching events are very likely to occur between two adjacent time steps. Fixed-time-step transient simulation suffers from the problem of a mismatch between passive switching events and the simulation step size.

[0004] PSCAD simulation requires inverting the node admittance matrix of the system network. With the continuous increase in DC transmission power demand and transmission voltage levels, MMC bridge arms require more submodules. Detailed simulation of ultra-large-scale MMC requires inverting ultra-high-order admittance matrices, making the simulation process extremely slow. Traditional fast simulation models commonly use two main approaches for equivalent modeling of switching elements: the L / C switching method and binary resistors. The L / C switching method avoids a large number of matrix inversion calculations, but the introduced virtual resistors cause power losses, affecting simulation accuracy. The binary resistor method changes the resistance value through switching control signals at integer multiples of the simulation step size, which is easy to implement, but ignores the passive switching events of diodes between adjacent steps. Passive switching events cause the actual output voltage of the submodule's port to deviate from the ideal value during the dead time, leading to dead-time effects such as voltage and current distortion, zero-current clamping, and a decrease in the output fundamental frequency voltage, affecting the operating characteristics of the MMC system.

[0005] In summary, there is an urgent need to conduct full-modal modeling research on fully hybrid MMCs with passive switching events under dead time. Summary of the Invention

[0006] The purpose of this invention is to propose a full-modal equivalent modeling method for fully-half hybrid modular multilevel converters to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for full-modal equivalent modeling of a fully-half hybrid modular multilevel converter includes:

[0009] S1. Introduce a dead-time delay to the conduction signal of the switching pulse, and analyze the working state of the full-bridge submodule with dead time under the actual switching pulse trigger signal in combination with the direction of the bridge arm current. Based on the circuit state under each switching combination and the influence of passive switching events on the working state of the submodule, it is divided into four modes: deterministic, latched, positive uncontrolled, and negative uncontrolled.

[0010] S2. For the active switching event-dominated deterministic mode, Thevenin equivalent based on ideal switching devices is adopted. For the passive switching event-dominated blocking, positive uncontrolled and negative uncontrolled modes, virtual diodes are introduced. The electrical branch information of the full-bridge valve segment is written using the Branch segment to connect the modes in series and establish a full-bridge valve segment full-mode equivalent model.

[0011] S3. Analyze the circuit state of the half-bridge sub-module containing dead zones and divide the circuit state into two modes: deterministic and latch-up. Consistent with the equivalent modeling approach of the full-bridge valve section in S2, establish a full-modal equivalent model of the half-bridge valve section.

[0012] S4. Connect the full-bridge valve section full-mode equivalent model and the half-bridge valve section full-mode equivalent model in series into the modular multilevel converter arm to obtain the full-mode equivalent model of the full-half hybrid modular multilevel converter.

[0013] Preferably, the full-bridge submodule with dead zone contains nine switch combinations. Based on the four modules, the switch combinations corresponding to the modes are determined to be 1001, 0110, 1010, and 0101; the switch combination corresponding to the interlocking module is 0000; the switch combinations corresponding to the positive uncontrolled mode are 1000 and 0001; and the switch combinations corresponding to the negative uncontrolled mode are 0100 and 0010.

[0014] Preferably, in the full-bridge valve section full-mode equivalent model, a single bridge arm of the modular multilevel converter is composed of multiple cascaded full-bridge sub-modules. Each sub-module operates independently, and their order on the bridge arm does not affect the system operation. The current circuit state of the sub-module is determined according to the switching control signal. The equivalent power sources of the same mode at the same simulation moment are algebraically superimposed. The equivalent voltage source and equivalent resistance under each mode are calculated by the following formula:

[0015]

[0016]

[0017] In the formula, U DFARM U BFARM U PFARM U NFARM These are the equivalent voltages for the full-bridge valve section in the determined, locked, positive uncontrolled, and negative uncontrolled modes, respectively; R DFARM R BFARM R PFARM R NFARM These are the equivalent resistance values ​​for the full-bridge valve section in the determined, locked, positive uncontrolled, and negative uncontrolled modes, respectively; N F N DF N BF N PF N NF These represent the total number of full-bridge submodules and the number of determined, interlocked, positive uncontrolled, and negative uncontrolled modes engaged in the valve section, respectively.

[0018] R DFSMeq_i and U DFSMeq_i Determine the equivalent resistance and equivalent voltage of the mode for the i-th full-bridge submodule; R BFSMeq_i and U BFSMeq_i R represents the equivalent resistance and equivalent voltage of the i-th full-bridge submodule in the locked-out mode, respectively; PFSMeq_i and U PFSMeq_i R represents the equivalent resistance and equivalent voltage of the i-th full-bridge submodule in the positive uncontrolled mode, respectively; NFSMeq_i and U NFSMeq_i R represents the equivalent resistance and equivalent voltage of the negative uncontrolled mode of the i-th full-bridge submodule, respectively; on This is the resistance value when the switch group is turned on.

[0019] Preferably, for the full-modal equivalent model of the half-bridge valve section, the circuit state determining the mode is determined only by the control signal, and Thevenin equivalent model based on ideal switching devices is adopted; the half-bridge valve section determined modal equivalent voltage U DHARM With equivalent resistance R DHARM The calculation formula is as follows:

[0020]

[0021] In the formula, U DHSMeq_i R DHSMeq_i Determine the modal equivalent voltage and resistance values ​​for the i-th half-bridge submodule respectively; u CH_i i CH _i represents the capacitor voltage and current of the i-th half-bridge submodule, respectively; N H N DH Determine the total number of half-bridge submodules and the number of modal inputs in the valve section; S HSM_i S represents the working state of the i-th half-bridge submodule. HSM_i =1 represents the input, S HSM_i =0 indicates a bypass.

[0022] The locked-down mode equivalent model introduces two virtual diodes D. VH1 With D VH2 1 virtual resistor R VBH and a set of resistors R BFSMeq_i With voltage source U BFSMeq_i Equivalent power supply in series. Equivalent voltage U in the half-bridge arm blocking mode. BHARM With equivalent resistance R BHARM The calculation formula is as follows:

[0023]

[0024] In the formula, N BH This represents the number of locking modes activated in the half-bridge valve section.

[0025] Preferably, the full-mode equivalent model of the hybrid modular multilevel converter is obtained by connecting the full-bridge valve section full-mode equivalent model and the half-bridge valve section full-mode equivalent model in series into the bridge arm.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] This invention employs the Thevenin equivalent based on ideal switching devices for modes dominated by active switching events, and introduces virtual diodes for modes dominated by passive switching events. It uses the electrical branch information of the full-half valve segment to connect each mode in series, and finally integrates it into the bridge arm of the modular multilevel converter to obtain a full-mode equivalent model of the full-half hybrid modular multilevel converter. The proposed full-mode equivalent modeling method for full-half hybrid modular multilevel converters, which considers dead time, achieves high accuracy under both steady-state and transient conditions while significantly accelerating performance. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings involved in the embodiments are now briefly described. Obviously, the drawings in the following description are merely illustrative of some embodiments of the present invention. For those skilled in the art, other forms of drawings can be constructed based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the Thevenin equivalent model based on an ideal switching device mentioned in Embodiment 1 of the present invention;

[0030] Figure 2 This is a schematic diagram of the equivalent modeling of the locked-down mode mentioned in Embodiment 1 of the present invention;

[0031] Figure 3 This is a schematic diagram of the equivalent modeling of the positive uncontrolled mode mentioned in Embodiment 1 of the present invention;

[0032] Figure 4 This is a schematic diagram of the equivalent modeling of the negative uncontrolled mode mentioned in Embodiment 1 of the present invention;

[0033] Figure 5 This is a schematic diagram of the equivalent modeling of the full-bridge valve section mentioned in Embodiment 1 of the present invention;

[0034] Figure 6 This is a topology diagram of the half-bridge submodule mentioned in Embodiment 1 of the present invention;

[0035] Figure 7 This is a schematic diagram of the equivalent modeling of the half-bridge valve section mentioned in Embodiment 1 of the present invention. Detailed Implementation

[0036] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0037] The following describes the full-modal equivalent modeling method for a fully-half hybrid modular multilevel converter proposed in this invention, with reference to the relevant accompanying drawings and specific examples.

[0038] Example 1:

[0039] This invention proposes a full-mode equivalent modeling method for a fully hybrid modular multilevel converter, including the following:

[0040] Step 1:

[0041] Please see Figure 1 The full-bridge submodule topology is as follows: Figure 1 As shown in (a), the submodule consists of 4 IGBT power transistors T Fi(i = 1, 2, 3, 4) and reverse parallel diode D Fi And a DC energy storage capacitor C F Composition. Under ideal complementary conduction switching pulse triggering, the full-bridge submodule has three operating states: positive connection, negative connection, and bypass. However, in practical engineering applications, to avoid shoot-through short-circuit faults in the complementary conduction switching devices on the same side of the submodule, a dead-time delay needs to be introduced into the conduction signal of the switching pulse.

[0042] The full-bridge submodule considering switch dead zones has nine switch combinations. Based on the circuit state under each switch combination and the influence of passive switching events on the submodule's operating state, they are divided into four modes: deterministic, latched, positive uncontrolled, and negative uncontrolled. Specifically, switch combinations 1001, 0110, 1010, and 0101 are deterministic modes; 0000 is a latched mode; 1000 and 0001 are positive uncontrolled modes; and 0100 and 0010 are negative uncontrolled modes. The circuit state in the deterministic mode is dominated by active switching events, while the circuit states in the latched, positive uncontrolled, and negative uncontrolled modes are dominated by passive switching events.

[0043] Step 2:

[0044] The following sections will model the four modes of the full-bridge submodule in step 1:

[0045] The circuit states that determine the modes are dominated by active switching events, and the Thevenin equivalent based on ideal switching devices is used. The modeling process is as follows: Figure 1 As shown. Figure 1 In (a), each switch group consisting of an IGBT and an anti-parallel diode can be considered as a binary resistor switching between high and low resistance values. When the switch group is on, the resistance value is equal to R. on When the switch group is turned off, the resistance value is equal to R. off In typical PSCAD electromagnetic transient simulation programs, the default value is the on-resistance R. on =0.01Ω, shut-off resistor R off =10 6 Ω. A discretized equivalent circuit is constructed for the capacitor using the widely applied trapezoidal integral method. The differential equation of the capacitor is:

[0046]

[0047] In the formula, i C (t) represents the current flowing through the capacitor; u C (t) represents the voltage across the capacitor; C represents the capacitance value.

[0048] Integrating equation (1), we get:

[0049]

[0050] In the formula, Δt is the unit simulation step size.

[0051] Discretizing equation (2) using the trapezoidal integration method, we get:

[0052]

[0053] From equation (3), we can see that the submodule capacitor C, after being discretized by trapezoidal integration, can be obtained from the equivalent resistance R. C Series equivalent voltage U Ceq The forms are equivalent, and their values ​​are all functions of time, as shown in equations (4) and (5). The update of the submodule capacitor voltage can be calculated by equation (3). Finally, the accompanying circuit of the full-bridge submodule is obtained, as shown in equation (4). Figure 1 As shown in (b). Here, diode D0 is used to ensure that the capacitor voltage of the submodule in the equivalent model does not have a negative value; R F1 R F2 R F3 and R F4 These represent the equivalent resistance of each switch group in the full-bridge submodule, and their values ​​are determined by the corresponding switch control signals.

[0054]

[0055] U Ceq (t)=u C (t-Δt)+R C ×i C (t-Δt) (5)

[0056] right Figure 1 (b) The accompanying circuit adopts the Thevenin equivalent based on ideal switching devices, which yields: Figure 1 (c) Thevenin equivalent circuit of the submodule. Equivalent parameter R of the i-th full-bridge submodule. DFSMeq_i and U DFSMeq_i The calculation formula is as follows:

[0057]

[0058] U DFSMeq_i (t)=(u CF_i (t-Δt)+R C ×i CF_i (t-Δt))×S FSM_i (7)

[0059] In the formula, u CF_i i CF_i These represent the capacitor voltage and current of the i-th full-bridge submodule, respectively; S FSM_i S represents the working state of the i-th full-bridge submodule. FSM_i =1 represents a positive input, S FSM_i=-1 represents negative input, S FSM_i =0 indicates a bypass.

[0060] The circuit state in the latch-up mode is dominated by passive switching events. A virtual diode is introduced, and the PSCAD interpolation algorithm is used to accurately locate the passive switching events of the actual diode. Its equivalent model is as follows: Figure 2 As shown. When the bridge arm current is greater than zero, the virtual diode D... VF1 D VF4 When the circuit is on and connected to the equivalent power supply, the analog submodule is in operation; when the bridge arm current is less than zero, the virtual diode D... VF2 D VF3 When the circuit is turned on, the equivalent power supply is negatively connected, simulating the negative input working state of the submodule. At this time, the operating state of the equivalent circuit in the latched mode is the same as that of the actual circuit. Specifically, the equivalent resistance R in the equivalent power supply... BFSMeq_i and equivalent voltage U BFSMeq_i The calculation formula is as follows:

[0061] R BFSMeq_i =R C (8)

[0062] U BFSMeq_i (t)=u C_i (t-Δt)+R C ×i C_i (t-Δt) (9)

[0063] Equivalent model of positive uncontrolled modes, such as Figure 3 As shown. Two virtual diodes D are introduced. VF5 With D VF6 1 virtual resistor R VPF and 1 set of equivalent resistance R PFSMeq_i With equivalent voltage source U PFSMeq_i Equivalent power sources in series. Where the virtual resistance R... VPF It is always equal to R on Equivalent resistance R PFSMeq_i With equivalent voltage source U PFSMeq_i The calculation formulas are the same as those in formulas (8)-(9). When the bridge arm current is greater than zero, diode D... VF5 When the circuit is open, forming a path with the equivalent power supply, the analog submodule is in operation; when the bridge arm current is less than zero, diode D... VF6 When the circuit is turned on, it forms a path with the virtual resistor, simulating the bypass operation state of the submodule. At this time, the operating state of the equivalent circuit in the uncontrolled mode is the same as that of the actual circuit.

[0064] Negative uncontrolled modal equivalent model such as Figure 4 As shown. Two virtual diodes D are introduced. VF7 With D VF8 1 virtual resistor RVNF and 1 set of equivalent resistance R NFSMeq_i With equivalent voltage source U NFSMeq_i Equivalent power sources in series. Where the equivalent resistance R... NFSMeq_i With equivalent voltage source U NFSMeq_i The calculation formulas are the same as those in formulas (8)-(9). When the bridge arm current is greater than zero, diode D... VF7 When the circuit is open, it forms a path with the virtual resistor, simulating the bypass operation of the submodule; when the bridge arm current is less than zero, diode D... VF8 When the circuit is turned on, it forms a path with the equivalent power supply, simulating the negative input working state of the submodule. At this time, the operating state of the negative uncontrolled equivalent circuit is the same as the operating state of the actual circuit.

[0065] Equivalent model of full-bridge valve section as follows Figure 5 As shown. A single MMC bridge arm consists of N F The system is composed of cascaded full-bridge submodules, each operating independently. The order of these submodules on the bridge arms does not affect system operation. Therefore, the current circuit state of each submodule is determined based on the switch control signal. The equivalent power sources for the same mode at the same simulation moment are algebraically superimposed. The equivalent voltage sources and equivalent resistances for each mode can be calculated using the following formula:

[0066]

[0067]

[0068] In the formula, U DFARM R DFARM U BFARM R BFARM U PFARM R PFARM U NFARM R NFARM These represent the equivalent voltage and resistance values ​​for the full-bridge determined, locked, positive uncontrolled, and negative uncontrolled modal valve sections, respectively; N F N DF N BF N PF N NF These represent the total number of sub-modules in the full bridge and the number of determined, interlocked, positive uncontrolled, and negative uncontrolled modes engaged in the valve section, respectively.

[0069] The PSCAD simulation platform manages code in segments, with each segment implementing its specific function. The Branch segment, for example, provides electrical branch information for the electrical network admittance matrix. Within the Branch segment, structures such as... Figure 5 The equivalent circuit of the full-bridge valve section is shown. An algorithm for the full-modal equivalent model of the full-bridge valve section, considering the switching dead time, is written in the DSDYN segment. Finally, the full-modal equivalent model of the full-bridge valve section is established.

[0070] Step 3:

[0071] Half-bridge submodule topology as follows Figure 6 As shown, the submodule consists of two IGBT power transistors T Hj (j=1,2) and anti-parallel diode D Hj And a DC energy storage capacitor C H Composition. Similar to the full-bridge submodule, the half-bridge submodule has two operating states under ideal switching trigger pulses: engaged and bypassed. Considering the dead time of the switches, the half-bridge submodule has a fully latched IGBT circuit state when switching between operating states. Therefore, it can be divided into two modes: deterministic and latched modes. Among them, switch combinations 10 and 01 are the deterministic mode, and 00 is the latched mode. Its modeling process is the same as that of the full-bridge; the full-modal equivalent model of the half-bridge valve section is briefly introduced below.

[0072] The full-modal equivalent model of the half-bridge valve section is as follows: Figure 7 As shown. The circuit state determining the mode is determined solely by the control signal; similarly, the Thevenin equivalent model based on ideal switching devices is used for this type of model. The half-bridge valve section determines the modal equivalent voltage U. DHARM With equivalent resistance R DHARM The calculation formula is as follows:

[0073]

[0074] In the formula, U DHSMeq_i R DHSMeq_i Determine the modal equivalent voltage and resistance values ​​for the i-th half-bridge submodule respectively; u CH_i i CH _i represents the capacitor voltage and current of the i-th half-bridge submodule, respectively; N H N DH Determine the total number of half-bridge submodules and the number of modal inputs in the valve section; S HSM_i S represents the working state of the i-th half-bridge submodule. HSM_i =1 represents the input, S HSM_i =0 indicates a bypass.

[0075] The locked-down mode equivalent model introduces two virtual diodes D. VH1 With D VH2 1 virtual resistor R VBH and a set of resistors R BFSMeq_i With voltage source U BFSMeq_i The equivalent power supply in series. When the bridge arm current is greater than zero, diode D... VH1 When the circuit is turned on, it forms a path with the equivalent power supply, simulating the state of the half-bridge submodule in operation; when the bridge arm current is less than zero, diode D... VH2When the circuit is turned on, it forms a path with the virtual resistor, simulating the bypass operation of the half-bridge submodule. At this time, the equivalent circuit operation is the same as the actual circuit operation. The equivalent voltage U of the half-bridge arm blocking mode is... BHARM With equivalent resistance R BHARM The calculation formula is as follows:

[0076]

[0077] In the formula, N BH This represents the number of locking modes activated in the half-bridge valve section.

[0078] Step 4:

[0079] Since a single MMC bridge arm is composed of a large number of cascaded full and half sub-modules, the operating state of each sub-module is determined by the nearest-level approximation modulation and the capacitor voltage equalization sorting algorithm, and they are independent of each other and do not interfere with each other. In order to obtain the full-modal equivalent model of the full-bridge valve section and the half-bridge valve section, it is only necessary to connect the full-modal equivalent model of the full-bridge valve section and the full-modal equivalent model of the half-bridge valve section in series into the bridge arm.

[0080] The full-mode equivalent modeling method for fully-half hybrid modular multilevel converters that considers dead zones proposed in this invention has high accuracy under both steady-state and transient conditions, while also showing significant acceleration effect.

[0081] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for full-modal equivalent modeling of a fully-half hybrid modular multilevel converter, characterized in that, include: S1. Introduce a dead-time delay to the conduction signal of the switching pulse, and analyze the working state of the full-bridge submodule with dead time under the actual switching pulse trigger signal in combination with the direction of the bridge arm current. Based on the circuit state under each switching combination and the influence of passive switching events on the working state of the submodule, it is divided into four modes: deterministic, latched, positive uncontrolled, and negative uncontrolled. S2. For the active switching event-dominated deterministic mode, Thevenin equivalent based on ideal switching devices is adopted. For the passive switching event-dominated blocking, positive uncontrolled and negative uncontrolled modes, virtual diodes are introduced. The electrical branch information of the full-bridge valve segment is written using the Branch segment to connect the modes in series and establish a full-bridge valve segment full-mode equivalent model. S3. Analyze the circuit state of the half-bridge sub-module containing dead zones and divide the circuit state into two modes: deterministic and latch-up. Consistent with the equivalent modeling approach of the full-bridge valve section in S2, establish a full-modal equivalent model of the half-bridge valve section. S4. Connect the full-bridge valve section full-mode equivalent model and the half-bridge valve section full-mode equivalent model in series into the modular multilevel converter arm to obtain the full-mode equivalent model of the full-half hybrid modular multilevel converter.

2. The method for full-mode equivalent modeling of a fully-half hybrid modular multilevel converter according to claim 1, characterized in that, The full-bridge submodule with dead zone contains nine switch combinations. Based on the four modules, the switch combinations corresponding to the modes are 1001, 0110, 1010, and 0101; the switch combination corresponding to the interlocking module is 0000; the switch combinations corresponding to the positive uncontrolled mode are 1000 and 0001; and the switch combinations corresponding to the negative uncontrolled mode are 0100 and 0010.

3. The method for full-mode equivalent modeling of a fully-half hybrid modular multilevel converter according to claim 2, characterized in that, In the full-bridge valve section full-mode equivalent model, a single bridge arm of the modular multilevel converter is composed of multiple cascaded full-bridge sub-modules. Each sub-module operates independently, and their order on the bridge arm does not affect the system operation. The current circuit state of the sub-module is determined according to the switching control signal. The equivalent power sources of the same mode at the same simulation moment are algebraically superimposed. The equivalent voltage source and equivalent resistance under each mode are calculated by the following formula: In the formula, U DFARM U BFARM U PFARM U NFARM These are the equivalent voltages for the full-bridge valve section in the determined, locked, positive uncontrolled, and negative uncontrolled modes, respectively; R DFARM R BFARM R PFARM R NFARM These are the equivalent resistance values ​​for the full-bridge valve section in the determined, locked, positive uncontrolled, and negative uncontrolled modes, respectively; N F N DF N BF N PF N NF These represent the total number of full-bridge submodules and the number of determined, interlocked, positive uncontrolled, and negative uncontrolled modes engaged in the valve section, respectively. R DFSMeq_i and U DFSMeq_i Determine the equivalent resistance and equivalent voltage of the mode for the i-th full-bridge submodule; R BFSMeq_i and U BFSMeq_i R represents the equivalent resistance and equivalent voltage of the i-th full-bridge submodule in the locked-out mode, respectively; PFSMeq_i and U PFSMeq_i R represents the equivalent resistance and equivalent voltage of the i-th full-bridge submodule in the positive uncontrolled mode, respectively; NFSMeq_i and U NFSMeq_i R represents the equivalent resistance and equivalent voltage of the negative uncontrolled mode of the i-th full-bridge submodule, respectively; on This is the resistance value when the switch group is turned on.

4. The method for full-mode equivalent modeling of a fully-half hybrid modular multilevel converter according to claim 3, characterized in that, For the full-modal equivalent model of the half-bridge valve section, the circuit state determining the mode is determined only by the control signal, and Thevenin equivalent model based on ideal switching devices is adopted; the equivalent voltage U of the half-bridge valve section is determined by the mode. DHARM With equivalent resistance R DHARM The calculation formula is as follows: In the formula, U DHSMeq_i R DHSMeq_i Determine the modal equivalent voltage and resistance values ​​for the i-th half-bridge submodule respectively; u CH_i i CH _i represents the capacitor voltage and current of the i-th half-bridge submodule, respectively; N H N DH Determine the total number of half-bridge submodules and the number of modal inputs in the valve section; S HSM_i S represents the working state of the i-th half-bridge submodule. HSM_i =1 represents the input, S HSM_i =0 indicates a bypass. The locked-down mode equivalent model introduces two virtual diodes D. VH1 With D VH2 1 virtual resistor R VBH and a set of resistors R BFSMeq_i With voltage source U BFSMeq_i Equivalent power supply in series. Equivalent voltage U in the half-bridge arm blocking mode. BHARM With equivalent resistance R BHARM The calculation formula is as follows: In the formula, N BH This represents the number of lockout modes activated in the half-bridge valve section.

5. The method for full-mode equivalent modeling of a fully-half hybrid modular multilevel converter according to claim 4, characterized in that, The full-mode equivalent model of the hybrid modular multilevel converter is obtained by connecting the full-bridge valve section full-mode equivalent model and the half-bridge valve section full-mode equivalent model in series into the bridge arm.

6. A computer device, characterized in that, The computer device includes a processor and a memory, wherein the memory stores at least one instruction, at least one program, code set, or instruction set, and the instruction, program, code set, or instruction set is loaded and executed by the processor to implement the full-modal equivalent modeling method for a fully-half hybrid modular multilevel converter as described in any one of claims 1-5.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores at least one instruction, at least one program, code set, or instruction set, which is loaded and executed by a processor to implement the full-modal equivalent modeling method for a fully-half hybrid modular multilevel converter as described in any one of claims 1-5.

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