A multi-module combined architecture type pulse electric field generator and an implementation method thereof

Abstract

This invention discloses a multi-module combined architecture pulse electric field generator and its implementation method. The output terminal of the three-phase rectifier circuit unit of the electric field generator is connected to a DC charging power unit. The output terminal of the DC charging power unit is connected to the input terminals of N Marx-LTD pulse power conversion unit modules. The input terminals of the N Marx-LTD pulse power conversion unit modules are connected in parallel, and the output terminals of the N Marx-LTD pulse power conversion unit modules are connected in series. Each Marx-LTD pulse power conversion unit module includes a Marx unipolar pulse generation circuit, an MRD magnetic reset branch circuit, and an LTD pulse transformer power transmission circuit connected in sequence. This invention can greatly reduce the influence of electromagnetic interference in the pulse power circuit on weak signals. The circuit structure is simple, the magnetic reset effect is obvious, the single-module MARX-LTD has stable operating performance, and it is easy to achieve modularization.

Description

Technical Field

[0001] This invention relates to the field of high-voltage pulsed electric field sterilization technology, and in particular to a multi-module combined architecture pulsed electric field generator and its implementation method. Background Technology

[0002] Liquid foods, such as fruit and vegetable juices, are rich in nutrients and water, providing essential nutrients for the human body. However, they also serve as ideal breeding grounds for bacteria, molds, and other microorganisms. The metabolic activities of these microorganisms alter certain components of food or change its visible, olfactory, and tactile properties (sensory characteristics), reducing or eliminating its edible value and causing spoilage. Therefore, sterilization is a crucial step in food processing. By inhibiting and killing spoilage and pathogenic bacteria, the shelf life of food can be extended, ensuring food safety. Sterilization methods for liquid foods, such as fruit and vegetable juices, include chemical and physical methods. Chemical methods, due to the toxic side effects of chemical residues, are gradually being phased out. Physical methods, which are residue-free, easily controlled, have high throughput, require simple equipment, and cause less environmental pollution, are gaining increasing attention.

[0003] Today, consumer habits are changing as the demand for fresh products continues to grow. Therefore, the fruit and vegetable juice industry has shifted its research focus to finding suitable sterilization technologies to produce food with minimal changes caused by the technology itself. It is well known that traditional physical sterilization techniques, such as heat sterilization, can extend the shelf life of juice, ensure its safety, and maximize the performance of juice processing. However, they may lead to the loss of nutritional, physicochemical, rheological, and sensory parameters. Because heat technology alters the natural flavor of food to some extent, such as texture, color, aroma, and nutritional characteristics, non-heat treatment technologies that preserve the natural characteristics of food have emerged.

[0004] Among numerous non-thermal treatment technologies, pulsed electric field (PEF) sterilization is currently the most effective and industrially promising non-thermal food treatment technology in the world, and it is being commercialized in the United States. Due to its low processing cost, PEF offers better economic benefits and stronger market competitiveness compared to traditional heat pasteurization. Therefore, if it can reach industrial application levels, it will inevitably revolutionize liquid food sterilization technology. However, PEF sterilization technology has remained in the laboratory stage and has not been widely applied in industrial production. While the reasons are varied, the biggest limiting factor is the lack of a stable, industrially suitable high-voltage pulse power supply.

[0005] Therefore, in order to promote the application of high-voltage pulse electric field non-thermal sterilization technology in the sterilization of fruit and vegetable juices, it is particularly important to design a high-voltage pulse electric field sterilization power supply with good performance that can meet the needs of industrial use.

[0006] The limitations of existing PEF-GPS power supply implementation technology are:

[0007] (1) The system architecture implemented by PEF-GPS is mostly implemented by multi-stage superposition scheme of Marx topology circuit. However, this scheme is limited by the output voltage level and the isolation withstand voltage of the auxiliary source, as well as the current carrying capacity of the power switching device, which limits the negative power level of the whole machine, making it bulky, difficult to troubleshoot single-stage faults, and having poor reliability.

[0008] (2) The single-stage / multi-stage linear pulse transformer (LTD) scheme can effectively reduce the current level of the primary winding, but it has high requirements for the voltage and power levels of the primary DC charging power supply. It requires a high-voltage power conversion stage after three-phase rectification input, and the reliability of the whole machine under normal operation is poor.

[0009] (3) At the same time, the LTD scheme requires an additional magnetic reset winding or active magnetic reset method, the transformer design and manufacturing structure is complex, and leakage magnetic noise seriously interferes with the control signal. Summary of the Invention

[0010] This invention provides a multi-module combined architecture pulse electric field generator and its implementation method to solve the problems of the prior art described in the background.

[0011] This invention provides a multi-module combined architecture pulse electric field generator, comprising: a three-phase rectifier circuit unit for converting three-phase AC power input from the mains into DC power; a DC charging power unit for boosting and converting the DC voltage output from the three-phase rectifier circuit unit into DC voltages of different voltage levels; and N Marx-LTD pulse power conversion unit modules for converting the DC voltages of different voltage levels into the required pulsed high voltage. The output terminal of the three-phase rectifier circuit unit is connected to the DC charging power unit, and the output terminal of the DC charging power unit is connected to the input terminals of the N Marx-LTD pulse power conversion unit modules. The input terminals of the N Marx-LTD pulse power conversion unit modules are connected in parallel, and the output terminals of the N Marx-LTD pulse power conversion unit modules are connected in series.

[0012] The Marx-LTD pulse power conversion unit module includes a Marx unipolar pulse generation circuit, an MRD magnetic reset branch circuit, and an LTD pulse transformer power transmission circuit, which are connected in sequence.

[0013] Furthermore, the input terminal of the three-phase rectifier circuit unit is connected to the AC input circuit, and the output terminals of the N Marx-LTD pulse power conversion unit modules are connected in series and then connected to the liquid load.

[0014] Furthermore, the Marx unipolar pulse generation circuit is composed of m-level Marx unit circuits connected in series, where m is a positive integer, and m satisfies the following inequality:

[0015]

[0016] Among them U aux_break U is the withstand voltage of the isolation auxiliary source for driving signal circuits. dc The output voltage of the DC charging power unit.

[0017] Furthermore, the Marx unit circuit includes a first N-type MOSFET, a second N-type MOSFET, a first diode, and a first capacitor. The cathode of the first diode is connected to the anode of the first capacitor and the drain of the first N-type MOSFET. The cathode of the first capacitor and the source of the second N-type MOSFET are connected to ground. The source of the first N-type MOSFET is connected to the drain of the second N-type MOSFET. The drains of the first N-type MOSFET and the second N-type MOSFET are respectively connected to the anode of the first diode and the cathode of the first capacitor in the next stage of the Marx unit circuit.

[0018] The positive terminal of the first diode and the negative terminal of the first capacitor in the first-stage Marx unit circuit are respectively connected to the positive and negative terminals of the DC charging power unit.

[0019] The drain of the second N-type MOSFET in the m-th stage Marx unit circuit is connected to the input terminal of the MRD magnetic reset branch circuit.

[0020] The gates of the first N-type MOSFET and the second N-type MOSFET are respectively connected to the output terminal of the controller.

[0021] Furthermore, the source and gate of the first N-type MOSFET are connected, and the source of the second N-type MOSFET is connected to one end of a first resistor, the other end of which is connected to the controller output.

[0022] Furthermore, the MRD magnetic reset branch circuit includes a third N-type MOSFET, a second diode, and a second resistor. The drain of the third N-type MOSFET is connected to the output terminal of the Marx unipolar pulse generation circuit, the source of the third N-type MOSFET is connected to the negative terminal of the second diode, the positive terminal of the second diode is connected to one end of the second resistor, the other end of the second resistor is connected to the ground terminal, and the gate of the third N-type MOSFET is connected to the output terminal of the controller.

[0023] Furthermore, the source of the third N-type MOSFET is connected to the input terminal of the LTD pulse transformer power transmission circuit, which is a power transformer.

[0024] This application also provides a method for implementing a multi-module combined architecture pulse electric field generator, including the following steps:

[0025] The three-phase rectifier circuit unit converts the three-phase AC power input from the mains into DC power.

[0026] The DC charging power unit boosts and converts the DC voltage output from the three-phase rectifier circuit unit into DC voltages of different voltage levels;

[0027] N Marx-LTD pulse power conversion unit modules convert the DC voltages of different voltage levels into the required pulses; wherein:

[0028] The Marx-LTD pulse power conversion unit module includes a Marx unipolar pulse generation circuit, an MRD magnetic reset branch circuit, and an LTD pulse transformer power transmission circuit connected in sequence.

[0029] The Marx unipolar pulse generator circuit outputs a square wave pulse.

[0030] The MRD magnetic reset branch circuit cuts off the connection between the transformer primary side and the common reference ground potential, providing a freewheeling path for the leakage inductance current and excitation current of the LTD pulse transformer power transmission circuit, while consuming leakage inductance energy.

[0031] The LTD pulse transformer power transmission circuit transmits the high-voltage pulse signal, processed by the MRD magnetic reset branch circuit, to the liquid load.

[0032] Furthermore, the third N-type MOSFET in the MRD magnetic reset branch circuit is driven by the discharge switch U of the Marx unipolar pulse generation circuit. gs_dis Before this, the tr_db time margin is given, ensuring zero-voltage turn-on of M; simultaneously, the discharge switch signal U... gs_dis After shutdown, the tf_db time margin is delayed to ensure zero-voltage shutdown of M.

[0033] Furthermore, the Marx unipolar pulse generation circuit is composed of m-level Marx unit circuits connected in series, and the m-level Marx unit circuits connected in series output a square wave pulse, where m is a positive integer and m satisfies the following inequality:

[0034]

[0035] Among them U aux_breakU is the withstand voltage of the isolation auxiliary source for driving signal circuits. dc The output voltage of the DC charging power unit.

[0036] The above-described at least one technical solution adopted in the embodiments of the present invention can achieve the following beneficial effects:

[0037] (1) The proposed single-module pulse power stage architecture uses a small number of Marx units to generate a high square wave pulse voltage amplitude, which reduces the difficulty of the boost conversion stage of the high-power DC charging unit in the front stage. At the same time, an industrial isolation withstand voltage level DC-DC module can be used as the power supply module for the signal circuit, which can greatly reduce the impact of electromagnetic interference of the pulse power circuit on weak signals.

[0038] (2) A novel MRD demagnetizing branch is proposed. The circuit structure is simple, the magnetic reset effect is obvious, and the single-module MARX-LTD has stable working performance.

[0039] (3) Based on the MRD demagnetizing branch, the timing relationship between the switching transistor of the control branch and the discharge switch of the MARX unit can be controlled to ensure the magnetic reset effect of the transformer. At the same time, the transistor M and diode D of the MRD branch have low voltage levels, which can be easily selected and obtained.

[0040] (4) The proposed new MARX-LTD module can be easily modularized, and the output voltage and power level can be easily expanded, making it suitable for different food sterilization applications. Attached Figure Description

[0041] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0042] Figure 1 This is a block diagram of the MARX-LTD multi-module combined architecture pulse electric field generator of the present invention;

[0043] Figure 2 This is a block diagram of the novel MARX-LTD single-module circuit structure of the present invention;

[0044] Figure 3 This is a circuit diagram of the novel MARX-LTD single module of the present invention;

[0045] Figure 4 A diagram illustrating the DC flux saturation problem in the transmission of unipolar pulse power by the magnetic core of a pulse transformer in existing technology;

[0046] Figure 5 The equivalent circuit diagram of a Marx unit cascaded LTD linear transformer;

[0047] Figure 6 The equivalent analysis circuit diagram for the two stages of a unipolar pulse cycle;

[0048] Figure 7 This is a schematic diagram of the novel MRD magnetic reset branch circuit structure proposed in this invention.

[0049] Figure 8 The equivalent analysis circuit diagram of the pulse period in the present invention with the addition of the MRD magnetic reset branch is shown in the figure.

[0050] Figure 9 Simulation waveforms of key points of the MARX-LTD single module with and without MRD demagnetization branch;

[0051] Figure 10 Here are the steady-state waveform details under the MRD control method;

[0052] Figure 11 Simulation waveform diagram for MRD branch parameter optimization;

[0053] Figure 12 This is a simulation schematic diagram of the superimposed output of three MARX-LTD modules and the single-module transformer of the present invention;

[0054] Figure 13 This is a comparison diagram of the superimposed output of the three MARX-LTD modules of the present invention and the primary current waveform of a single-module transformer. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0056] The technical solutions provided by the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0057] like Figure 1The diagram shown is a block diagram of the overall circuit structure of the MARX-LTD multi-module combined architecture pulse electric field generator proposed in this invention. The entire unit consists of a three-phase rectifier circuit unit, a DC charging power unit, N Marx-LTD pulse power conversion unit modules, and the final target food liquid load for processing. The AC input uses three-phase AC power from the mains, which is converted into DC power by the three-phase controllable rectifier circuit unit and then boosted to different voltage levels (Udc) by the DC charging power unit. The N Marx-LTD pulse power conversion unit modules are connected in parallel at their input terminals, sharing the same DC charging bus (Udc). The output is the secondary side of the LTD transformer of each module, connected in series to form the required high-voltage pulse (Upulse).

[0058] The innovation of this invention lies in the proposed novel Marx-LTD pulse power conversion unit module, the specific internal circuit structure of which is shown in the figure below. Figure 2 As shown in the diagram. The main power section consists of three parts: a Marx unipolar pulse generation circuit, an MRD magnetic reset branch circuit, and an LTD pulse transformer power transmission circuit. The specific circuit structure is as follows: Figure 3 As shown.

[0059] Figure 3 The given circuit structure presents a 3-stage Marx unit as an illustrative example. The number of stages m (where m is a positive integer) of the Marx unipolar module generation circuit depends on the breakdown voltage Uaux_break of the isolation auxiliary source of the drive signal circuit, and the following inequality exists:

[0060]

[0061] Among them U aux_break U is the withstand voltage of the isolation auxiliary source for driving signal circuits. dc The output voltage of the DC charging power unit is [voltage value missing]. The square wave pulse power output by the Marx unipolar pulse generation circuit unit is sent to the primary side of the linear transformer LTD through the MRD branch. The number of turns on the primary side of the transformer is Np, and the number of turns on the secondary side is Ns.

[0062] Analysis of DC flux saturation problem in traditional single-pulse input LTD

[0063] Because the primary winding of a linear pulse transformer is always supplied with unipolar DC pulse power, the transformer suffers from magnetic flux saturation. That is, after a few pulses of power-on operation, the DC charging power supply will experience overcurrent. The saturated primary winding of the magnetic core is equivalent to a short circuit, which short-circuits the output terminal of the DC charging power supply.

[0064] The schematic diagram of the LTD core magnetization process is shown below. Figure 4As shown in (a), the initial operating point of the LTD transformer core is the origin O, where both its magnetic field strength and magnetic induction intensity are 0. After the first pulse is applied, the operating point of the core changes to B1, which is the increase in magnetic induction intensity ΔB.

[0065] ΔB=B1 (2)

[0066] When the first pulse ends and the magnetic field strength drops to 0, the residual magnetic induction intensity generated due to the hysteresis effect of the magnetic core is B. r1 During the second pulse input process, the magnetic induction intensity changed from B. r1 Adding the corresponding magnetic flux density increment ΔB again, we get:

[0067] B2 = B r1 +ΔB (3)

[0068] Similarly, when the p-th pulse is given, the operating point of the magnetic core reaches point A. After the p-th pulse ends, the residual magnetic field strength of the magnetic core is the residual magnetic field B corresponding to the limiting hysteresis curve. r When the static operating point hysteresis loop is reached under the repetitive pulse input, such as... Figure 4 As shown in (b). Therefore, it is necessary to control the value of the magnetic flux density increment ΔB under specific pulse input conditions, which can effectively control the pulse input parameters of LTD. The parameter expression of ΔB is as follows:

[0069]

[0070] in:

[0071] U pri —Amplitude of the pulse voltage on the input side of the linear transformer;

[0072] t pulse —The duration of the pulse amplitude on the input side of the linear transformer;

[0073] N p —This refers to the number of turns in the primary winding of the transformer;

[0074] S—the cross-sectional area of ​​the magnetic flux of the transformer core;

[0075] K T —This represents the characteristic parameter constant of the transformer core.

[0076] The equivalent circuit corresponding to its LTD transformer is as follows: Figure 5 As shown, the transformer is equivalent to an ideal transformer with a ratio of Np:Ns, and the magnetizing inductance L m Original edge leakage L lk_1 The parasitic resistance R1 of the primary winding and the leakage inductance L of the secondary winding. lk_2 Parasitic resistance R2 of secondary winding and load R load .

[0077] The linear transformer input side is supplied with a unipolar square wave pulse power from the Marx unit, divided into two states: the pulse discharge stage (State I) and the pulse termination stage (State II). The equivalent analysis circuit diagrams for the LTD at different stages are shown below. Figure 6 As shown.

[0078] In State I: The amplitude of the Marx cell pulse discharge voltage is U marx This generates a corresponding excitation current I. lm (Very small) and primary current I pri At the same time, a secondary current I is induced on the secondary side. sec :

[0079]

[0080]

[0081]

[0082] For load R load Provide pulsed power current. Since the target sterilized liquid food is equivalent to a low-resistivity load, I... sec The waveform and U pulse similar.

[0083] In State II phase: the pulse power voltage ends, U marx With a voltage of 0V, the excitation current theoretically remains constant, and the voltage U of the transformer primary winding... pri for:

[0084] U pri =0V (8)

[0085] The applied voltage to the magnetizing inductor has no negative voltage component, the volt-second product is unbalanced, and the magnetizing current I... lm As the number of pulses gradually increases until the magnetic core saturates, a short-circuit overcurrent problem will occur.

[0086] Based on the above mechanism analysis of the core saturation problem of LTD under Marx unipolar pulse, the main function of magnetic reset is to reduce the magnetic induction intensity increment ΔB under single pulse, provide negative voltage for the excitation inductor, remove the excitation current, and achieve volt-second balance of the excitation inductor, so as to realize the stable and reliable transmission of Marx unipolar pulse power.

[0087] Based on this problem analysis model, this invention proposes an MDR magnetic reset branch, such as... Figure 7As shown, the switching transistor M is used to disconnect the transformer primary side from the common reference ground potential, the power diode D is used to provide a freewheeling path for the transformer leakage inductance current and magnetizing current, and the resistor R is used to dissipate the leakage inductance energy and provide a negative voltage for the magnetizing inductance to achieve volt-second balance.

[0088] The timing logic relationship between the switching transistor M of the MRD branch and the discharge switching transistor of the Marx cell under the given Marx unipolar pulse in State I and State II, is as follows: Figure 8 As shown.

[0089] Among them, the third N-type MOSFET in the MRD magnetic reset branch circuit is driven by the discharge switch U of the Marx unipolar pulse generation circuit. gs_dis Before this, the tr_db time margin is given, ensuring zero-voltage turn-on of M; simultaneously, the discharge switch signal U... gs_dis After turn-off, a time margin of tf_db is allowed for turn-off, thus ensuring zero-voltage turn-off of M. This timing control method can effectively avoid the high withstand voltage problem of the switching transistor in MRD, and the selection of M only needs to ensure its current carrying capacity.

[0090] Meanwhile, during State I, before the high-voltage pulse from the Marx unit arrives, M has already been turned on, and the power path with LTD is complete, allowing LTD to normally transmit pulse power to the load. During State II, after a time interval of tf_db, the magnetizing current and leakage inductance current flow through the freewheeling branch of RD, forming a negative voltage U across R. R It consumes leakage inductance energy and excitation current, and resets the excitation inductor.

[0091] according to Figure 8 The proposed MRD magnetic reset and control method was tested for feasibility in circuit simulation software. The simulation schematic of the Marx-LTD single module is shown below. Figure 3 As shown, the simulation results with and without the MRD branch under normal operating conditions (0.5s) are compared to, for example... Figure 9 As shown. Given a DC charging voltage of 1kV, a 3kV square wave pulse is generated using a 3-stage Marx unit. The pulse duration is 1s, the pulse frequency is 1kHz, the LTD transformer turns ratio is 1:1, and the equivalent load impedance is 50R.

[0092] Under simulation conditions, the primary current I of the LTD transformer without the MRD branch is... pri As time goes by, I pri A linear increase to 1kA would immediately saturate in a practical circuit. However, after adding the proposed MRD branch, I... priThe output of the square wave pulse current remains consistently stable at around 60A, and its detailed magnified waveform is as follows: Figure 10 As shown.

[0093] Depend on Figure 9 Normal comparison chart and Figure 10 The magnified view after adding the MRD shows that the LTD can stably output a 3kV square wave pulse voltage, with a pulse current amplitude of 60A under a 50Ω load resistance. This demonstrates the feasibility and effectiveness of the proposed MRD magnetic reset branch and control method.

[0094] Although the proposed MRD branch is effective in addressing the problem of LTD saturation caused by the Marx output unipolar pulse, whether the MRD branch magnetic reset method has practical application value in engineering circuits still needs to be examined to determine the impact of the voltage and current levels of each component in the branch, as well as the parameter values, on the circuit function. Figure 11 Quantitative simulation results of the voltage and current of each component in the MRD branch are given.

[0095] Depend on Figure 11 As shown in (a), the maximum withstand voltage of the switching transistor M is 632V, and its maximum current is the load current of 60A. The withstand voltage of the diode D is the amplitude of the pulse voltage output by the Marx unit, which is 3kV, and the current is the excitation current. Therefore, the selection of M and D only requires simple and common high-current power transistors and high-voltage silicon stacked diodes to achieve the target function well. At the same time, the negative voltage resistor R affects the magnitude and duration of the leakage inductance current. The smaller the value, the larger the current and the longer the duration, but the overall resistance power consumption is very small.

[0096] The MRD magnetic reset branch, proposed by combining the Marx unipolar pulse generator and the LTD transformer, constitutes the novel MARX-LTD modular circuit unit proposed in this invention. This modular structure also enables modular integration and supports the expansion of power and voltage through parallel input and series output of multiple modules. Its feasibility simulation experiments are as follows... Figure 12 , Figure 13 As shown, where Figure 12 This is a schematic diagram illustrating the principle of the simulation experiment. Figure 13 Under normal operating conditions (0.5s), the pulse voltage and current output by the whole machine, as well as the current waveforms ipri1, ipri2, and ipri3 on the primary side of each LTD transformer.

[0097] Depend on Figure 12 , Figure 13Simulation results show that parallel input and series output of multiple modules can effectively expand power and voltage, with the pulse voltage amplitude increasing to about 9kV and the pulse current being about 90A under the same 50R load resistance. At the same time, the primary current waveforms of the LTD of the three modules do not show saturation problems, and the waveforms of the three modules almost overlap, which confirms the feasibility of the proposed scheme superposition.

[0098] In summary, the present invention has the following effects:

[0099] (1) A single-module structure of a high-voltage Marx unipolar pulse generator unit coupled with a linear transformer is proposed. A small number of Marx units are used to generate a high square wave pulse voltage amplitude, which reduces the difficulty of the boost conversion stage of the high-power DC charging unit. At the same time, an industrial isolation withstand voltage level DC-DC module can be used as the power supply module for the signal circuit. The use of an industrial-grade power supply module with a high power supply common mode rejection ratio can greatly reduce the impact of electromagnetic interference of the pulse power circuit on weak signals.

[0100] (2) A novel MRD (Mosfet-Resistor-Diode, MRD) demagnetizing branch is proposed. It does not require the addition of a demagnetizing winding on the common transformer core. It can effectively reduce the negative voltage generated by the leakage current of the transformer primary winding and the discharge pulse timing of the switching MOSFET and the Marx power supply. It can also balance and reset the transformer volt-second product, thereby reducing the decrease of the transformer magnetic induction intensity increment ΔB under a single pulse. The circuit structure is simple, the magnetic reset effect is obvious, and the single-module MARX-LTD has stable working performance.

[0101] (3) Based on the MR demagnetizing branch, the timing relationship between the switching transistor of the branch and the discharge switch of the MARX unit is controlled by the control method. That is, the switching signal of the branch transistor and the discharge switch signal are reserved with sufficient advance turn-on time margin and lag turn-off time margin, which can ensure effective magnetic reset of the transformer. At the same time, the transistor M and diode D of the MRD branch are subjected to low voltage levels, which can be easily selected and obtained.

[0102] (4) The proposed new MARX-LTD module can be easily modularized. It adopts a structure with parallel DC input and series transformer output, which can easily expand the output voltage and power levels and is suitable for different food sterilization applications.

[0103] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A multi-module combined architecture pulsed electric field generator, characterized by, include: A three-phase rectifier circuit unit for converting three-phase AC power input from the mains to DC power; a DC charging power unit for boosting and converting the DC voltage output from the three-phase rectifier circuit unit to different voltage levels of DC voltage; and N Marx-LTD pulse power conversion unit modules for converting the different voltage levels of DC voltage into the required pulsed high voltage. The output terminal of the three-phase rectifier circuit unit is connected to the DC charging power unit, and the output terminal of the DC charging power unit is connected to the input terminals of the N Marx-LTD pulse power conversion unit modules. The input terminals of the N Marx-LTD pulse power conversion unit modules are connected in parallel, and the output terminals of the N Marx-LTD pulse power conversion unit modules are connected in series. The Marx-LTD pulse power conversion unit module includes a Marx unipolar pulse generation circuit, an MRD magnetic reset branch circuit, and an LTD pulse transformer power transmission circuit, which are connected in sequence. The MRD magnetic reset branch circuit includes a third N-type MOSFET, a second diode, and a second resistor. The drain of the third N-type MOSFET is connected to the output terminal of the Marx unipolar pulse generation circuit, the source of the third N-type MOSFET is connected to the negative terminal of the second diode, the positive terminal of the second diode is connected to one end of the second resistor, the other end of the second resistor is connected to the ground terminal, and the gate of the third N-type MOSFET is connected to the output terminal of the controller. The source of the third N-type MOSFET is connected to the input terminal of the LTD pulse transformer power transmission circuit.

2. A multi-module combined architecture pulsed electric field generator according to claim 1, characterized in that, The input terminal of the three-phase rectifier circuit unit is connected to the AC input circuit, and the output terminals of the N Marx-LTD pulse power conversion unit modules are connected in series and then connected to the liquid load.

3. The multi-module combined architecture pulsed electric field generator of claim 1, wherein, The Marx unipolar pulse generation circuit is composed of m-level Marx unit circuits connected in series, where m is a positive integer, and m satisfies the following inequality: wherein is the isolation auxiliary source withstand voltage value of the driving signal circuit, is the DC charging power unit output voltage.

4. The multi-module combined architecture pulsed electric field generator of claim 3, wherein, The Marx unit circuit includes a first N-type MOSFET, a second N-type MOSFET, a first diode, and a first capacitor. The cathode of the first diode is connected to the anode of the first capacitor and the drain of the first N-type MOSFET. The cathode of the first capacitor and the source of the second N-type MOSFET are connected to ground. The source of the first N-type MOSFET is connected to the drain of the second N-type MOSFET. The drains of the first and second N-type MOSFETs are respectively connected to the anode of the first diode and the cathode of the first capacitor in the next stage of the Marx unit circuit. The positive terminal of the first diode and the negative terminal of the first capacitor in the first-stage Marx unit circuit are respectively connected to the positive and negative terminals of the DC charging power unit. The drain of the second N-type MOSFET in the m-th stage Marx unit circuit is connected to the input terminal of the MRD magnetic reset branch circuit; The gates of the first N-type MOSFET and the second N-type MOSFET are respectively connected to the output terminal of the controller.

5. A multi-module combined architecture pulsed electric field generator according to claim 4, wherein, The source and gate of the first N-type MOSFET are connected, and the source of the second N-type MOSFET is also connected to one end of a first resistor, the other end of which is connected to the output of the controller.

6. A multi-module combined architecture pulsed electric field generator according to claim 5, wherein, The source of the third N-type MOSFET is connected to the input terminal of the LTD pulse transformer power transmission circuit, which is a power transformer.

7. A method for implementing a multi-module combined architecture pulsed electric field generator, characterized in that, Includes the following steps: The three-phase rectifier circuit unit converts the three-phase AC power input from the mains into DC power. The DC charging power unit boosts and converts the DC voltage output from the three-phase rectifier circuit unit into DC voltages of different voltage levels; N Marx-LTD pulse power conversion unit modules convert the DC voltages of different voltage levels into the required pulses; wherein: The Marx-LTD pulse power conversion unit module includes a Marx unipolar pulse generation circuit, an MRD magnetic reset branch circuit, and an LTD pulse transformer power transmission circuit connected in sequence. The Marx unipolar pulse generator circuit outputs a square wave pulse. The MRD magnetic reset branch circuit disconnects the connection between the transformer primary side and the common reference ground potential, providing a freewheeling path for the leakage inductance current and excitation current of the LTD pulse transformer power transmission circuit, while consuming leakage inductance energy. The LTD pulse transformer power transmission circuit transmits the high-voltage pulse signal processed by the MRD magnetic reset branch circuit to the liquid load. The MRD magnetic reset branch circuit includes a third N-type MOSFET, a second diode, and a second resistor. The drain of the third N-type MOSFET is connected to the output terminal of the Marx unipolar pulse generation circuit, the source of the third N-type MOSFET is connected to the negative terminal of the second diode, the positive terminal of the second diode is connected to one end of the second resistor, the other end of the second resistor is connected to the ground terminal, and the gate of the third N-type MOSFET is connected to the controller output terminal. The source of the third N-type MOSFET is connected to the input terminal of the LTD pulse transformer power transmission circuit.

8. The method of claim 7, wherein the method further comprises: The third N-type MOSFET in the MRD magnetic reset branch circuit is driven by the discharge switch signal of the Marx unipolar pulse generation circuit. Before the given time margin of tr_db, the third N-type MOSFET is turned on, thus ensuring zero-voltage turn-on; simultaneously, the discharge switching signal... After being turned off, the tf_db time margin is delayed to ensure zero-voltage turn-off of the third N-type MOSFET.

9. The method of claim 7, wherein the method further comprises: The Marx unipolar pulse generation circuit is composed of m-level Marx unit circuits connected in series. The m-level Marx unit circuits connected in series output a square wave pulse, where m is a positive integer and m satisfies the following inequality: wherein is the isolation auxiliary source withstand voltage value of the driving signal circuit, is the direct current charging power unit output voltage.

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