An Electromagnetic Launch Control Method Based on SHEPWM Considering Dead-Time Effect
By optimizing the SHEPWM waveform using Fourier transform and particle swarm optimization, the impact of the dead zone effect on electromagnetic exploration was resolved, enabling efficient and low-cost electromagnetic detection that meets the exploration needs of complex terrain and deep mineral resources.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA UNIV OF MINING & TECH
- Filing Date
- 2023-08-04
- Publication Date
- 2026-07-17
Smart Images
Figure CN116995947B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to an electromagnetic launch control method based on SHEPWM that takes into account the dead-zone effect, belonging to the field of frequency domain electromagnetic launch control technology in geophysical exploration technology. Background Technology
[0002] As shallow mineral resources are gradually depleted, we need to develop mineral resources in complex terrains and deep layers. Therefore, current research focuses on achieving efficient and high-precision exploration of complex terrains and deep geological information. Electromagnetic exploration mainly includes frequency domain and time domain electromagnetic methods, both of which can be used for focused electromagnetic detection at specific target depths. However, the detection accuracy is limited by the primary field generated by the transmitted waveform. Frequency domain electromagnetic methods primarily use pseudo-random waveforms. To achieve high-precision exploration, multiple transmissions and receptions are required to increase the required frequency points, resulting in low detection efficiency and high exploration costs. Time domain electromagnetic methods mainly use bipolar trapezoidal waves. To improve energy utilization and reduce switching losses, the quality of the transmitted waveform is poor, leading to decreased detection accuracy. Furthermore, the magnitude of the transmitted current affects the detection depth, thus requiring increased transmission power and placing higher demands on the transmitting equipment.
[0003] To address the aforementioned issues, a precise mathematical model is established using Specific Harmonic Elimination Pulse Width Modulation (SHEPWM) technology to design a method for outputting the optimal transmission current for targets at arbitrary detection depths, achieving high-efficiency and low-cost detection. Against the backdrop of depth-focused electromagnetic precision detection, the transmission control method based on SHEPWM technology is investigated.
[0004] In electromagnetic detection transmitting circuits, SHEPWM technology can eliminate specific unwanted harmonics and generate deeply focused waveforms. However, in hardware transmitting circuit design, a dead time needs to be set to avoid bridge arm shoot-through, which causes a deviation between the actual output waveform and the ideal waveform, thus affecting harmonic distribution. In particular, the higher the output waveform frequency, the greater the impact of the dead time; therefore, it is necessary to minimize or avoid the impact of the dead time on the harmonic distribution of SHEPWM technology. Existing research on dead time compensation strategies is only applicable to unipolar SHEPWM waveforms with 1 / 4 and 1 / 2 cycles, and cannot be applied to bipolar SHEPWM waveforms with full-cycle asymmetry. Summary of the Invention
[0005] The technical problem to be solved by this invention is to provide an electromagnetic emission control method based on SHEPWM that takes into account the dead-zone effect. By selecting the SHEPWM output waveform that takes into account the dead-zone effect of the full-cycle asymmetry, the dead-zone part of the waveform is set to 0 during Fourier transform. By calculating the required switching angle, the DC and harmonic component parameters of the inverter output waveform can be precisely controlled. At the same time, the signal source is allowed to transmit only the required main frequency, thereby achieving high-efficiency electromagnetic detection.
[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:
[0007] An electromagnetic launch control method based on SHEPWM considering dead-time effect includes the following steps:
[0008] Step 1: For the full-cycle asymmetric SHEPWM waveform, Fourier transform analysis is used to decompose it into the sum of harmonic components, fundamental components and DC components. Let the amplitude of the transmitting current harmonics be the controlled component to obtain the SHEPWM nonlinear equation set.
[0009] Step 2: Based on the actual requirements of the exploration depth, determine the amplitude of the main frequency of the emission current using the skin depth formula and the law of conservation of energy;
[0010] Step 3: Taking the dead zone effect into account, based on the actual circuit waveform with dead zone, perform Fourier transform again to obtain the SHEPWM nonlinear equation set considering the dead zone effect.
[0011] Step 4: Use the particle swarm optimization algorithm to iteratively calculate the SHEPWM nonlinear equations considering the dead zone effect, and obtain the solution results of the full-cycle asymmetric SHEPWM switching angle considering the dead zone.
[0012] As a preferred embodiment of the present invention, the specific process of step 1 is as follows:
[0013] Step 11: By performing a Fourier transform on the time-domain waveform of the full-cycle asymmetric SHEPWM waveform with respect to time t, the waveform is decomposed into the sum of harmonic components, fundamental components, and DC components.
[0014]
[0015] Among them, U SHE (t) represents the full-cycle asymmetric SHEPWM waveform, where a0 is the DC component, and a i b i All are Fourier coefficients, N is the number of switching angles per unit period, and ω is the angular velocity of the SHEPWM time-domain waveform;
[0016] Step 12: List the DC component a0 and the Fourier coefficients a0 of each controlled harmonic component corresponding to the bipolar full-cycle asymmetric SHEPWM waveform. i b i :
[0017]
[0018]
[0019]
[0020] Among them, U d The inverter input DC voltage, α k Let α be the switching angle, k = 1, 2, ..., N, 0 < α1 < α2 < ... < α N <2π, θ i Let A be the phase of the i-th harmonic. i The amplitude of the dominant frequency of the standard square wave time-domain transmitted current;
[0021] Step 13: Based on the actual requirements of the exploration depth, select the number of switching angles N per unit period, thus obtaining the corresponding SHEPWM nonlinear equation set:
[0022]
[0023] As a preferred embodiment of the present invention, the specific process of step 2 is as follows:
[0024] Based on the actual requirements of the electromagnetic exploration depth H, the frequency band range of the dominant frequency of the emission current is determined using the skin depth formula:
[0025]
[0026] Where, δ FD Where σ1 is the skin depth, f is the conductivity, and f is the frequency.
[0027] The amplitude of the dominant frequency of the controllable frequency source current is determined according to the law of conservation of energy:
[0028]
[0029] Among them, A i U is the amplitude of the dominant frequency of the standard square wave time-domain transmitted current. d is the DC input voltage of the inverter, and i is the i-th harmonic.
[0030] As a preferred embodiment of the present invention, in step 3, the SHEPWM nonlinear equations considering the dead-time effect are as follows:
[0031]
[0032] Where a0 is the DC component, a i b i All are Fourier coefficients, U d The inverter input DC voltage, i is the i-th harmonic, α k Let α be the switching angle, k = 1, 2, ..., N, where N is the number of switching angles per unit period. d Let A be the dead zone angle occupied by the dead time within a single period. iLet θ be the amplitude of the dominant frequency of the standard square wave time-domain transmitted current. i Let be the phase of the i-th harmonic.
[0033] As a preferred embodiment of the present invention, the specific process of step 4 is as follows:
[0034] Step 41: Initialize the maximum number of iterations (Maxiterations), the counter set (setcount), and the counter (count); set the function change tolerance (F_tolerance);
[0035] Step 42: At each iteration, calculate the best fitness value F_best, and calculate the absolute value of the change between the best fitness of the current iteration and the best fitness of the previous iteration, F_av_change.
[0036] Step 43: Determine whether the absolute value of the fitness change F_av_change is less than the function change tolerance F_tolerance. If so, increment the counter count by 1; otherwise, clear the counter count to zero.
[0037] Step 44: If the current iteration count exceeds the maximum iteration count Maxiterations, then exit the loop and obtain the optimal solution; if the current iteration count does not exceed the maximum iteration count Maxiterations, and the count value is greater than the count setting value setcount, it means that the optimal solution is within a certain fluctuation range, then exit the loop directly.
[0038] Step 45: Determine whether the optimal fitness value F_best meets the accuracy requirements of the solution. If not, return to step 41 until the accuracy requirements are met and the optimal solution is obtained, then end the calculation.
[0039] A computer device includes a memory, a processor, and a computer program stored in the memory and capable of running on the processor, wherein the processor executes the computer program to implement the steps of the SHEPWM-based electromagnetic emission control method considering dead-time effects as described above.
[0040] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the electromagnetic emission control method based on SHEPWM considering dead-time effects as described above.
[0041] Compared with the prior art, the present invention, employing the above technical solution, has the following technical effects:
[0042] This invention utilizes SHEPWM technology for practical applications in electromagnetic exploration, considering the impact of dead-zone effects on electromagnetic emissions in actual circuits. It addresses the limitation of existing dead-zone compensation strategies, which are only applicable to unipolar SHEPWM waveforms with 1 / 4 and 1 / 2 cycles, and cannot be applied to bipolar SHEPWM waveforms with full-cycle asymmetry. For the detailed exploration needs of complex terrain and deep mineral resources, considering the influence of dead-zone effects on harmonic distribution in actual SHEPWM waveform circuits, a set of nonlinear equations for full-cycle asymmetric SHEPWM that meets exploration requirements is established. An optimized particle swarm optimization algorithm is used to solve the equations to obtain the corresponding switching angles. Through dead-zone compensation, the frequency domain information of the full-cycle asymmetric SHEPWM frequency-focused waveform conforms to the desired specific harmonic amplitude. Attached Figure Description
[0043] Figure 1 This is a schematic diagram of a single-phase full-bridge inverter circuit that outputs a full-cycle asymmetric SHEPWM waveform.
[0044] Figure 2 This is a flowchart of the electromagnetic launch control method based on SHEPWM considering dead-time effect according to the present invention;
[0045] Figure 3 This is a flowchart of the optimized particle swarm optimization algorithm for solving this invention;
[0046] Figure 4 This is a frequency domain information diagram of an ideal switch full-cycle asymmetric SHEPWM.
[0047] Figure 5 This is the frequency domain information diagram of the full-cycle asymmetric SHEPWM after adding the dead zone;
[0048] Figure 6 These are the ideal full-cycle asymmetric SHEPWM waveform and the SHEPWM waveform with added symmetric dead time, where (a) is the waveform with dead time and (b) is the ideal waveform.
[0049] Figure 7 This is a frequency domain information diagram of the full-cycle asymmetric SHEPWM dead-time compensation of the present invention. Detailed Implementation
[0050] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.
[0051] like Figure 1As shown, the single-phase full-bridge inverter circuit controls the output of a full-cycle asymmetrical SHEPWM waveform, and the SHEPWM control pulse generates four drive signals; the single-phase full-bridge circuit consists of four IGBT devices Q1, Q2, Q3, and Q4, which are used to convert DC voltage into AC voltage.
[0052] like Figure 2 As shown, this invention proposes an electromagnetic launch control method based on SHEPWM that considers the dead-time effect. The SHEPWM waveform is offline modulated using pre-stored switching angles to take the dead-time problem into account. After comparative analysis, a method of symmetrically adding the dead time is selected to output a full-cycle asymmetrical SHEPWM waveform, and the shaded area represents the influence of the dead time on the output voltage and the ideal voltage.
[0053] The electromagnetic launch control method based on SHEPWM considering dead-time effect of the present invention has the following specific process:
[0054] S1: For the full-cycle asymmetric SHEPWM waveform, Fourier transform analysis is used to decompose it into the sum of harmonic components, fundamental components and DC components. The amplitude of the transmitting current harmonics is set as the controlled component to obtain the SHEPWM nonlinear equation set.
[0055] S11: Analyze the SHEPWM waveform using Fourier transform, decomposing it into the sum of harmonic components, fundamental components, and DC components:
[0056]
[0057] S12: Based on the bipolar full-cycle asymmetric SHEPWM waveform, list the corresponding DC component a0 and the Fourier coefficients a of each controlled harmonic. i b i The expression is as follows:
[0058]
[0059]
[0060]
[0061] 0 < α1 < α2 < ... < α N <2π
[0062] In the formula, U d The inverter input DC voltage, N is the number of switching angles per unit cycle, and α k (k = 1, 2, ..., N) represents the switching angle, θ i Let be the phase of the i-th harmonic, and we have:
[0063]
[0064] S13: Based on the actual requirements of the exploration depth, select the number of switching angles N per unit period, and thus obtain the corresponding SHEPWM nonlinear equation set one:
[0065] (1) Set the Fourier coefficients a of each controlled harmonic. i and b i Compared with the ideal emission current spectrum A i equal;
[0066] (2) Set the DC component a0 to be equal to 0, and the phase θ of the harmonics. i It equals 0.
[0067]
[0068] S2: Based on the exploration depth requirements, the frequency band range of the main frequency of the transmission current is determined using the skin depth formula, and the amplitude of the main frequency of the controllable frequency source current is determined according to the law of conservation of energy.
[0069] Based on the actual requirements of the electromagnetic exploration depth H, the frequency band range of the dominant frequency of the emission current is determined using the skin depth formula:
[0070]
[0071] Where, δ FD Let σ1 be the skin depth, σ1 be the electrical conductivity, and f be the frequency. As can be seen from the above formula, the exploration depth is related to the observation frequency and the earth's electrical conductivity. When the earth's resistivity remains constant for a given terrain, the main factor related to the exploration depth is the frequency.
[0072] The amplitude of the dominant frequency of the controllable frequency source current is determined according to the law of conservation of energy:
[0073]
[0074] Among them, A i It is the amplitude of the dominant frequency of the standard square wave time-domain transmitted current, and the amplitude A of the harmonics is set. i No more than 4U d / π, where i is the harmonic order.
[0075] S3: Taking the dead-time effect into account, based on the actual circuit waveform with dead time, perform a new Fourier transform to obtain the desired SHEPWM nonlinear equation set.
[0076] Let i a times, i b times, i c The amplitude of the subharmonic is A i , and i a <i b <i c Then the number of switching angles can be set to N = 2(ic +1), with phase 0, amplitudes of all other harmonics 0, and DC component 0, substituting into nonlinear equation set one yields:
[0077]
[0078] Taking the dead-time effect into account, based on the actual circuit waveform with a dead time, a new Fourier transform is performed, setting the dead-time portion of the waveform to 0, thus obtaining the desired SHEPWM nonlinear equation set two:
[0079]
[0080] S4: When solving nonlinear equations using the particle swarm optimization algorithm, the electromagnetic launch control method based on SHEPWM, which considers the dead-zone effect, eliminates the initial value limitation in solving for the switching angle. During iterative calculations, whether the desired switching angle α is obtained is determined by whether the iteration deviation is less than the tolerance of the function change. k .
[0081] Let the number of switching N = 20, the amplitude of the 7th, 8th, and 9th harmonics be 0.5, the phase be 0, the amplitude of all other harmonics be 0, and the DC component be 0. Substituting these values into the above equation, we obtain the system of equations for the waveform to be generated:
[0082]
[0083] like Figure 3 When using the particle swarm optimization algorithm to solve nonlinear equations, the switching angle solution is freed from the initial value constraint and performs iterative calculations. Whether the desired switching angle α is obtained is determined by whether the iteration deviation is less than the tolerance of the function's change. k The solution results are shown in Table 1. Figure 4 The diagram shows the frequency domain information of the full-cycle asymmetric SHEPWM under an ideal switch.
[0084] Table 1. Solution of switching angles for full-cycle asymmetric SHEPWM
[0085]
[0086] observe Figure 5 After introducing a 5µs dead zone, the harmonic distribution of the output waveform based on SHEPWM will change in a way that does not meet the expected setting value. This causes the set amplitudes of the 7th, 8th, and 9th harmonics to be smaller than the theoretical setting value of 0.5, affecting the transmission response.
[0087] Figure 6 (b) represents the ideal full-cycle asymmetric SHEPWM waveform. Taking the dead-time effect into account, Fourier transform analysis is performed, as shown below. Figure 6(a) is the SHEPWM waveform after adding a symmetrical dead-time mode, using the full-cycle asymmetrical sine component coefficient a. i for:
[0088]
[0089] Similarly, after adding the symmetrical dead-time method, the cosine component coefficient b based on the SHEPWM waveform... i for:
[0090]
[0091] Considering the inclusion of a symmetrical dead-time mode, the full-cycle asymmetrical DC component a0 selected based on the SHEPWM waveform is:
[0092]
[0093] In summary, considering the case where N is even when a symmetric dead zone is added, the nonlinear equations for the full-cycle asymmetric SHEPWM are as follows:
[0094]
[0095] The switching angle limitation relationship needs to take into account the dead zone as follows:
[0096] 0 < α1 < α2 < … < α N <2π
[0097] Where α d With T d The relationship is as follows:
[0098]
[0099] The nonlinear equations above still contain the setpoint for the DC component and the parameter information for each harmonic. Each harmonic component is divided into sine and cosine components, forming two sets of equations. The DC component requires one set of equations for control. However, after adding the symmetrical dead-time method, the right side of the equations changes. It even fluctuates continuously with different dead-time and control frequencies.
[0100] With a dead time of 5µs, taking the full-cycle asymmetric SHEPWM waveform described above, where the transmitting current frequency is set to the 7th, 8th, and 9th harmonics, as an example, and using a fundamental frequency of 2kHz for simulation analysis, by considering symmetrical dead time compensation, the equations for the generated waveform are transformed into the following form:
[0101]
[0102] The optimal solution to the SHEPWM dead-time compensation equation is obtained using the particle swarm optimization algorithm, thereby obtaining a pseudo-random specific switching angle of the SHEPWM that meets practical requirements. The specific steps are as follows:
[0103] We will design a strategy based on the particle swarm optimization algorithm that can automatically exit the iterative loop when the fitness requirement is met.
[0104] (1) Initialize the maximum number of iterations (Maxiterations), the counter setcount, and the counter count;
[0105] (2) Define “F_tolerance” for the change in function, which is generally a very small positive number;
[0106] (3) In each iteration, calculate the best fitness value F_best, and calculate the change between this fitness and the best fitness in the previous iteration. Generally, take it as the absolute value F_av_change.
[0107] (4) Determine whether the absolute value of the fitness change F_av_change is less than the relative size of the function change tolerance. If it is, increment the counter count by 1; otherwise, clear the counter count to 0.
[0108] (5) Through repeated iterations, the analysis results are as follows:
[0109] ① If the number of iterations exceeds the maximum iteration value Maxiterations, the loop is exited directly, and the optimal solution is obtained.
[0110] ② If the maximum number of iterations (Maxiterations) has not been exceeded and the count value is greater than the set count value (setcount), it means that the optimal solution is within a certain fluctuation range. In this case, the loop is exited directly, the search is ended, and time is saved.
[0111] (6) Determine whether the optimal fitness value F_best meets the accuracy requirements of the solution. If not, continue looping (1)-(5) until the requirements are met and the optimal solution is obtained, and then end the operation.
[0112] In terms of computational performance, an adaptive weighting system combined with a shrinkage factor is used to avoid getting trapped in local optima. A tolerance for function change is set as a relevant quantity. Before each loop, the absolute value of the fitness change is calculated and compared. If the absolute value of the fitness change is consistently less than the predetermined tolerance, it indicates that the searched particle is in the optimal position, the solution is converging, and the loop can be automatically exited. Regarding the angle constraint, considering practical considerations, a SHEPWM waveform emission setting is implemented to add constraints on the switching angle. If the requirements are not met, the particle swarm is repeatedly initialized and recalculated. In terms of solution accuracy, a precision requirement is set. If the optimal solution obtained still does not meet the high-precision setting, repeated operations are necessary until a satisfactory solution is obtained.
[0113] By adding new loop instructions to meet the actual needs of exploration, and re-substituting the loop calculation if the requirements are not met, the solution results of the full-cycle asymmetric SHEPWM switching angle considering the dead zone are shown in Table 2. Figure 7 This is a frequency domain information diagram of the full-cycle asymmetric SHEPWM dead-time compensation of the present invention.
[0114] Table 2 shows the solution for the full-cycle asymmetric SHEPWM switching angle considering the dead zone.
[0115]
[0116] By comparing and analyzing the harmonic distributions in three states—ideal switch, with dead zone added, and considering dead zone response—the calculation derivation considering dead zone response can compensate for the problem of reduced amplitude of specific harmonics after adding dead zone. This makes the amplitudes of the 7th, 8th, and 9th harmonics increase further and approach 0.5 compared to the case with dead zone added. It can also solve the problem that the amplitudes of some controllable harmonics were not zero due to the dead zone, and eliminate them to approach zero.
[0117] Based on the same inventive concept, embodiments of this application provide a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the aforementioned electromagnetic emission control method based on SHEPWM considering dead-time effects.
[0118] Based on the same inventive concept, embodiments of this application provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the aforementioned electromagnetic emission control method based on SHEPWM considering dead-time effects.
[0119] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.
[0120] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.
[0121] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.
[0122] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.
[0123] The above embodiments are merely illustrative of the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solutions based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.
Claims
1. An electromagnetic launch control method based on SHEPWM considering dead-time effect, characterized in that, Includes the following steps: Step 1: For the full-cycle asymmetric SHEPWM waveform, Fourier transform analysis is used to decompose it into the sum of harmonic components, fundamental components and DC components. Let the amplitude of the transmitting current harmonics be the controlled component to obtain the SHEPWM nonlinear equation set. Step 2: Based on the actual requirements of the exploration depth, determine the amplitude of the dominant frequency of the emission current using the skin depth formula and the law of conservation of energy; the specific process is as follows: Based on the actual requirements of the electromagnetic exploration depth H, the frequency band range of the dominant frequency of the emission current is determined using the skin depth formula: ， in, To reach skin depth, f is the electrical conductivity, and f is the frequency. The amplitude of the dominant frequency of the controllable frequency source current is determined according to the law of conservation of energy: ， in, The amplitude of the dominant frequency of the standard square wave time-domain transmitted current. Input DC voltage to the inverter. For the first Second harmonics; Step 3: Taking the dead zone effect into account, based on the actual circuit waveform with dead zone, perform Fourier transform again to obtain the SHEPWM nonlinear equation set considering the dead zone effect. The SHEPWM nonlinear equations considering the dead-time effect are as follows: ， in, The DC component, , All are Fourier coefficients. For the switching angle, , The number of switching angles per unit period. This represents the dead zone angle occupied by the dead zone time within a single period. For the first The phase of the subharmonic; Step 4: Use the particle swarm optimization algorithm to iteratively calculate the SHEPWM nonlinear equations considering the dead zone effect, and obtain the solution results of the full-cycle asymmetric SHEPWM switching angle considering the dead zone.
2. The electromagnetic launch control method based on SHEPWM considering dead-time effect according to claim 1, characterized in that, The specific process of step 1 is as follows: Step 11: By performing a Fourier transform on the time-domain waveform of the full-cycle asymmetric SHEPWM waveform with respect to time t, the waveform is decomposed into the sum of harmonic components, fundamental components, and DC components. ， in, It is a full-cycle asymmetric SHEPWM waveform. Angular velocity of the SHEPWM time-domain waveform; Step 12: List the DC components corresponding to the bipolar full-cycle asymmetric SHEPWM waveform. and the Fourier coefficients of each controlled harmonic component , : ， ， ， in, ; Step 13: Based on the actual requirements of the exploration depth, select the number of switching angles N per unit period, thus obtaining the corresponding SHEPWM nonlinear equation set: 。 3. The electromagnetic launch control method based on SHEPWM considering dead-time effect according to claim 1, characterized in that, The specific process of step 4 is as follows: Step 41: Initialize the maximum number of iterations (Maxiterations), the counter set (setcount), and the counter (count); set the function change tolerance (F_tolerance); Step 42: At each iteration, calculate the best fitness value F_best, and calculate the absolute value of the change between the best fitness of the current iteration and the best fitness of the previous iteration, F_av_change. Step 43: Determine whether the absolute value of the fitness change F_av_change is less than the function change tolerance F_tolerance. If so, increment the counter count by 1; otherwise, clear the counter count to zero. Step 44: If the current iteration count exceeds the maximum iteration count Maxiterations, then exit the loop and obtain the optimal solution; if the current iteration count does not exceed the maximum iteration count Maxiterations, and the count value is greater than the count setting value setcount, it means that the optimal solution is within a certain fluctuation range, then exit the loop directly. Step 45: Determine whether the optimal fitness value F_best meets the accuracy requirements of the solution. If not, return to step 41 until the accuracy requirements are met and the optimal solution is obtained, then end the calculation.
4. A computer device comprising a memory, a processor, and a computer program stored in the memory and capable of running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the electromagnetic launch control method based on SHEPWM considering dead-time effect as described in any one of claims 1 to 3.
5. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the electromagnetic launch control method based on SHEPWM considering dead-time effect as described in any one of claims 1 to 3.