A pulse generator based on magnetic induction current sharing in parallel SiCMOSFETs

Abstract

A magnetic induction current-sharing parallel SiC MOSFET pulse generator includes: a control signal generation module, an opto-isolation drive module, a solid-state switch drive module, a magnetic induction current-sharing module, a Marx pulse generator output module, and a load. This invention achieves a simpler and more efficient output of larger pulse current and power from the Marx generator through parallel SiC MOSFET switches. The circuit topology is simple, the parameters are flexibly adjustable, and multiple modules can be stacked. The magnetic induction current-sharing technology used in this invention solves the problem of uneven current distribution between parallel switching devices, ensuring the reliability and stability of the high-current output of the parallel SiC MOSFET pulse generator. The pulse output voltage and current amplitude, pulse width, and pulse frequency of the magnetic induction current-sharing parallel SiC MOSFET pulse generator proposed in this invention are all flexibly adjustable.

Description

Technical Field

[0001] This invention relates to the field of pulsed power source technology, specifically to a pulse generator based on magnetic induction current sharing and parallel SiCMOSFETs. Background Technology

[0002] In recent years, pulsed power technology has been widely used in food processing, microalgae treatment, plasma reactions, and underwater discharge. In these applications, due to their low-impedance load characteristics, in addition to the need for high-voltage pulse output, the ability to generate large currents is also required. Pulse generators are also developing towards higher power. Simultaneously, to meet the demands of low-cost, short-pulse-width, and high-repetition-rate large-scale industrial applications, higher requirements are placed on pulse sources and their switching devices. Typical methods for generating high-voltage pulses include magnetic compression, Blummlein pulse forming lines, linear transformer drivers (LTDs), and Marx. Magnetic compression has a complex structure, and Blummlein pulse forming lines require impedance matching. LTDs can generate large-current pulse outputs, but due to their low efficiency, large size, and pulse width limitation by the magnetic core, large-scale industrial applications are difficult to achieve. Compared to the above pulse generation methods, all-solid-state Marx circuits have advantages such as simple structure, flexible and adjustable parameters, and the ability to stack multiple modules, meeting more application needs and having a broader prospect for application. Marx can achieve high-voltage output through multi-module stacking, but its output current is limited by the switching devices used. Currently, the rated current of a single commercially available SiC MOSFET is still very limited, and increasing the rated output current of an all-solid-state Marx generator is a problem that needs to be solved.

[0003] Existing Marx inter-stage parallel solutions can output high-current pulses on low-impedance loads. However, the parallel module configuration increases the size and structural complexity of the pulse generator, and the lack of current sharing between the parallel modules leads to current imbalances that pose a significant challenge to the stable operation of the entire pulse generator. In contrast, parallel SiC MOSFETs offer a simpler and more efficient solution for increasing the output current and power of Marx pulse generators. However, due to the dispersion of device parameters and the lack of consistency in circuit parasitic parameters, current imbalances inevitably occur in different parallel switching branches when two or more SiC MOSFETs are connected in parallel. These imbalances include static current imbalances after turn-on and transient current imbalances generated during switching dynamics. Ensuring current sharing among parallel SiC MOSFETs is a prerequisite for the long-term stable operation of the generator and remains an unresolved challenge.

[0004] Existing Marx inter-stage parallel schemes can output high-current pulses on low-impedance loads. However, the parallel module scheme increases the size and structural complexity of the pulse generator. At the same time, no current sharing measures are taken between the parallel modules, and the current imbalance between the modules poses a great challenge to the long-term reliable and stable operation of the entire pulse generator. Summary of the Invention

[0005] The purpose of this invention is to provide a magnetic induction current sharing parallel SiC MOSFET pulse generator, comprising: a control signal generation module, an opto-isolation drive module, a solid-state switch drive module, a magnetic induction current sharing module, a Marx pulse generator output module, and a load.

[0006] The control signal generation module is used to generate solid-state switch control signals.

[0007] The opto-isolation drive module is used to eliminate the high-potential floating of solid-state switches.

[0008] After receiving the solid-state switch control signal, the solid-state switch driver module controls the on and off of each switch in the Marx pulse generator output module, as well as the on and off time.

[0009] The magnetic induction current sharing module is used to eliminate uneven current between solid-state switches.

[0010] The Marx pulse generator output module is used to generate pulse signals and input the pulse signals into the load.

[0011] The circuit topology of the pulse generator is shown below:

[0012] Remember the power supply The end containing the positive electrode is called terminal I, and the end containing the negative electrode is called terminal J. Terminal J is grounded.

[0013] The I terminal is connected to a diode. anode, diode Cathode connection capacitor Then connect to the J end.

[0014] The diode Cathode connected magnetic induction current sharing parallel switch module Connected to diode cathode, diode The anode is connected to the J terminal.

[0015] The magnetic induction current sharing parallel switch module Including magnetic induction coupling coils Solid-state switches Solid-state switches , where i = 1, 2, ..., n, and n is a positive integer.

[0016] Magnetic induction coupling coil It includes a first transmission line, a second transmission line, and a magnetic ring.

[0017] The first and second transmission lines are symmetrically wound around both sides of the magnetic ring.

[0018] Describe the magnetic induction coupling coil One end of the first transmission line is One end, the other end is One end of the second transmission line is... One end, the other end is end.

[0019] The Terminal connection diode The cathode, the Terminal connection diode The cathode.

[0020] The Terminal connection solid-state switch drain, solid-state switch The source is connected to the diode. The cathode.

[0021] The Terminal connection solid-state switch drain, solid-state switch The source is connected to the diode. The cathode.

[0022] The diode Cathode connection capacitor Connected to diode The anode.

[0023] The diode Anode-connected diode The cathode, where k = 2, 3, ..., n.

[0024] The diode Anode-connected diode The cathode.

[0025] The diode Cathode connection load Connected to diode The anode.

[0026] Furthermore, the pulse generator also includes a host computer.

[0027] The host computer generates circuit parameters and transmits them to the control signal generation module, which then generates solid-state switch control signals.

[0028] Furthermore, when solid-state switches Solid-state switches When the circuit is turned on, the branch currents in the first and second transmission lines flow into two coupled coils with the same number of turns on the magnetic core, generating magnetic fluxes in opposite directions in the magnetic circuit.

[0029] Furthermore, the current difference between the two branches generates magnetic flux in the magnetic core, inducing an electromotive force in the primary coil. The secondary coil induces an electromotive force. The electromotive force drives the unbalanced current to remain zero. As shown below:

[0030] (1)

[0031] In the formula, The magnetizing inductance of the magnetically coupled coil. The current difference within the coil is denoted by t, where t is time.

[0032] Furthermore, the magnetizing inductance of the magnetic induction coupling coil of the magnetic induction current sharing parallel switch module... and leakage As shown below:

[0033] (2)

[0034] In the formula, This represents the number of turns in the coil. , These are the outer diameter and inner diameter of the magnetic core, respectively. This represents the current difference within the coil. denoted as ρ, where ρ is the relative permeability of the magnetic core. is the vacuum permeability. This is the current flowing through the coil. This is the coil length.

[0035] Among them, the magnetic flux density in the magnetic core As shown below:

[0036] (3)

[0037] In the formula, is the magnetic permeability. denoted as , where is the magnetic field strength in the magnetic core. This represents the current within the first transmission line. This refers to the current within the second transmission line.

[0038] Leakage flux density in air As shown below:

[0039] (4)

[0040] In the formula, The magnetic field strength in the air.

[0041] The cross-sectional area S of the magnetic core is shown below:

[0042] (5)

[0043] In the formula, h is the height of the magnetic core.

[0044] Furthermore, the solid-state switch Solid-state switches The dynamic response time of the unbalanced current during the transient process of conduction. As shown below:

[0045] (6)

[0046] In the formula, The magnetizing inductance of the magnetically coupled coil. The leakage inductance of the magnetically coupled coil. solid-state switch The drain parasitic inductance, solid-state switch The source parasitic inductance, solid-state switch The resistance between the drain and the source This is the variable resistor during the dynamic switching process.

[0047] Furthermore, the solid-state switch Solid-state switches After full conduction, the magnetizing inductor For unbalanced current The time constant for the inhibitory effect As shown below:

[0048] (7)

[0049] In the formula, solid-state switch The on-resistance.

[0050] Furthermore, the pulse width range for the magnetic induction coupling coil to suppress unbalanced current stress between solid-state switches is 50ns-1000ns.

[0051] Furthermore, the pulse output voltage amplitude, pulse width, and pulse frequency of the pulse generator are all adjustable.

[0052] The voltage amplitude range of the pulse generator output is 500V-5kV.

[0053] The pulse width output by the pulse generator ranges from 50ns to 1000ns.

[0054] The pulse generator outputs pulses in the range of 1 Hz - 1 kHz.

[0055] Furthermore, the solid-state switch Solid-state switches Both use MOSFET switches.

[0056] The technical advantages of this invention are undeniable. This invention proposes a pulse generator based on magnetic induction current balance (MICB) parallel SiC MOSFETs. By employing MICB technology, only one coupling coil is used to effectively suppress the switching transients and static unbalanced currents that occur during pulse generation, solving the problem of uneven current distribution between parallel switching devices and enabling a larger pulse current output from the Marx generator. The developed Marx prototype has an output voltage of 5kV, an output current of 50A, and a repetition rate of 10kHz. Within a pulse width range of 50-1000ns, the magnetic induction coupling coil effectively suppresses the unbalanced current stress between the parallel SiC MOSFETs, ensuring the reliability and stability of the pulse generator's high-current output.

[0057] The beneficial effects of this invention include:

[0058] 1. By using parallel SiC MOSFET switches, the Marx generator achieves larger pulse current and power output more simply and efficiently. The circuit topology is simple, the parameters are flexibly adjustable, and multiple modules can be stacked.

[0059] 2. The magnetic induction current sharing technology adopted solves the problem of uneven current between parallel switching devices, ensuring the reliability and stability of the high current output of the parallel SiCMOSFET pulse generator.

[0060] 3. The pulse output voltage and current amplitude, pulse width, and pulse frequency of the pulse generator based on magnetic induction current sharing parallel SiC MOSFETs proposed in this invention are all flexibly adjustable. Attached Figure Description

[0061] Figure 1 This is a schematic diagram of the various modules of the present invention.

[0062] Figure 2This is a schematic diagram of the Marx main circuit topology for magnetic induction current sharing parallel switches.

[0063] Figure 3 This is a schematic diagram of the Marx equivalent circuit for a magnetic induction current-sharing parallel switch.

[0064] Figure 4 This is a schematic diagram of the physical model of a magnetic induction coupling coil. Figure 4 (a) is a schematic diagram of the front of the coil. Figure 4 (b) is a schematic diagram of the coil cross-section.

[0065] Figure 5 This is a schematic diagram of the equivalent circuit model of magnetic induction current sharing during the switching dynamic process.

[0066] Figure 6 This is a schematic diagram of the equivalent circuit model of magnetic induction current sharing after the switch is fully turned on.

[0067] Figure 7 This is a schematic diagram of a magnetic induction current sharing simulation circuit.

[0068] Figure 8 This is a schematic diagram of the simulated switching current waveforms for different branches of a parallel SiC MOSFET. Figure 8 (a) is a schematic diagram without flow equalization measures. Figure 8 (b) is a schematic diagram of magnetic induction current sharing.

[0069] Figure 9 This is a schematic diagram of the experimental testing platform.

[0070] Figure 10 This is a schematic diagram of the top-level PCB for a single-level Marx.

[0071] Figure 11 This is a schematic diagram of the current waveform in the parallel switch branch of the Marx generator. Figure 11 (a) is a schematic diagram without flow equalization measures. Figure 11 (b) is a schematic diagram of magnetic induction current sharing.

[0072] Figure 12 This is a schematic diagram of the Marx output waveform under different pulse widths. Figure 12 (a) is a schematic diagram of the output current waveform. Figure 12 (b) is a schematic diagram of the output voltage waveform. Detailed Implementation

[0073] The present invention will be further described below with reference to embodiments, but it should not be construed that the scope of the present invention is limited to the following embodiments. Various substitutions and modifications made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention should be included within the scope of protection of the present invention.

[0074] Example 1:

[0075] See Figures 1 to 12 A magnetic induction current sharing parallel SiC MOSFET pulse generator includes: a control signal generation module, an opto-isolation drive module, a solid-state switch drive module, a magnetic induction current sharing module, a Marx pulse generator output module, and a load.

[0076] The control signal generation module is used to generate solid-state switch control signals.

[0077] The opto-isolation drive module is used to eliminate the high-potential floating of solid-state switches.

[0078] After receiving the solid-state switch control signal, the solid-state switch driver module controls the on and off of each switch in the Marx pulse generator output module, as well as the on and off time.

[0079] The magnetic induction current sharing module is used to eliminate uneven current between solid-state switches.

[0080] The Marx pulse generator output module is used to generate pulse signals and input the pulse signals into the load.

[0081] The circuit topology of the pulse generator is shown below:

[0082] Remember the power supply The end containing the positive electrode is called terminal I, and the end containing the negative electrode is called terminal J. Terminal J is grounded.

[0083] The I terminal is connected to a diode. anode, diode Cathode connection capacitor Then connect to the J end.

[0084] The diode Cathode connected magnetic induction current sharing parallel switch module Connected to diode cathode, diode The anode is connected to the J terminal.

[0085] The magnetic induction current sharing parallel switch module Including magnetic induction coupling coils Solid-state switches Solid-state switches , where i = 1, 2, ..., n, and n is a positive integer.

[0086] Magnetic induction coupling coil It includes a first transmission line, a second transmission line, and a magnetic ring.

[0087] The first and second transmission lines are symmetrically wound around both sides of the magnetic ring.

[0088] Describe the magnetic induction coupling coil One end of the first transmission line is One end, the other end is One end of the second transmission line is... One end, the other end is end.

[0089] The Terminal connection diode The cathode, the Terminal connection diode The cathode.

[0090] The Terminal connection solid-state switch drain, solid-state switch The source is connected to the diode. The cathode.

[0091] The Terminal connection solid-state switch drain, solid-state switch The source is connected to the diode. The cathode.

[0092] The diode Cathode connection capacitor Connected to diode The anode.

[0093] The diode Anode-connected diode The cathode, where k = 2, 3, ..., n.

[0094] The diode Anode-connected diode The cathode.

[0095] The diode Cathode connection load Connected to diode The anode.

[0096] Example 2:

[0097] A pulse generator based on magnetic induction current sharing parallel SiC MOSFETs is described in Embodiment 1. Furthermore, the pulse generator also includes a host computer.

[0098] The host computer generates circuit parameters and transmits them to the control signal generation module, which then generates solid-state switch control signals.

[0099] Example 3:

[0100] A pulse generator based on magnetic induction current sharing in parallel SiC MOSFETs, the main technical contents of which are described in any one of Embodiments 1 to 2, further, when the solid-state switch Solid-state switches When the circuit is turned on, the branch currents in the first and second transmission lines flow into two coupled coils with the same number of turns on the magnetic core, generating magnetic fluxes in opposite directions in the magnetic circuit.

[0101] Example 4:

[0102] A pulse generator based on magnetic induction current sharing parallel SiC MOSFETs is described in any one of embodiments 1 to 3. Further, the current difference between the two branches generates magnetic flux in the magnetic core, inducing an electromotive force in the primary coil. The secondary coil induces an electromotive force. The electromotive force drives the unbalanced current to remain zero. As shown below:

[0103] (1)

[0104] In the formula, The magnetizing inductance of the magnetically coupled coil. The current difference within the coil is denoted by t, where t is time.

[0105] Example 5:

[0106] A pulse generator based on magnetic induction current sharing parallel SiC MOSFETs, the main technical contents of which are described in any one of embodiments 1 to 4, further comprising the magnetizing inductance of the magnetic induction coupling coil of the magnetic induction current sharing parallel switching module. and leakage As shown below:

[0107] (2)

[0108] In the formula, This represents the number of turns in the coil. , These are the outer diameter and inner diameter of the magnetic core, respectively. This represents the current difference within the coil. denoted as ρ, where ρ is the relative permeability of the magnetic core. is the vacuum permeability. This is the current flowing through the coil. This is the coil length.

[0109] Among them, the magnetic flux density in the magnetic core As shown below:

[0110] (3)

[0111] In the formula, is the magnetic permeability. denoted as , where is the magnetic field strength in the magnetic core. This represents the current within the first transmission line. This refers to the current within the second transmission line.

[0112] Leakage flux density in air As shown below:

[0113] (4)

[0114] In the formula, The magnetic field strength in the air.

[0115] The cross-sectional area S of the magnetic core is shown below:

[0116] (5)

[0117] In the formula, h is the height of the magnetic core.

[0118] Example 6:

[0119] A pulse generator based on magnetic induction current sharing parallel SiC MOSFETs, the main technical contents of which are described in any one of embodiments 1 to 5, further, the solid-state switch Solid-state switches The dynamic response time of the unbalanced current during the transient process of conduction. As shown below:

[0120] (6)

[0121] In the formula, The magnetizing inductance of the magnetically coupled coil. The leakage inductance of the magnetically coupled coil. solid-state switch The drain parasitic inductance, solid-state switch The source parasitic inductance, solid-state switch The resistance between the drain and the source This is the variable resistor during the dynamic switching process.

[0122] Example 7:

[0123] A pulse generator based on magnetic induction current sharing parallel SiC MOSFETs, the main technical contents of which are described in any one of Embodiments 1 to 6, further wherein the solid-state switch Solid-state switches After full conduction, the magnetizing inductor For unbalanced current The time constant for the inhibitory effect As shown below:

[0124] (7)

[0125] In the formula, solid-state switch The on-resistance.

[0126] Example 8:

[0127] A pulse generator based on magnetic induction current sharing parallel SiC MOSFETs is provided. The main technical contents are described in any one of Embodiments 1 to 7. Further, the pulse width range of the magnetic induction coupling coil for suppressing unbalanced current stress between solid-state switches is 50ns-1000ns.

[0128] Example 9:

[0129] A pulse generator based on magnetic induction current sharing parallel SiC MOSFETs is provided. The main technical contents are described in any one of Embodiments 1 to 8. Furthermore, the pulse output voltage amplitude, pulse width, and pulse frequency of the pulse generator are all adjustable.

[0130] The voltage amplitude range of the pulse generator output is 500V-5kV.

[0131] The pulse width output by the pulse generator ranges from 50ns to 1000ns.

[0132] The pulse generator outputs pulses in the range of 1 Hz - 1 kHz.

[0133] Example 10:

[0134] A pulse generator based on magnetic induction current sharing parallel SiC MOSFETs, the main technical contents of which are described in any one of embodiments 1 to 9, further wherein the solid-state switch Solid-state switches Both use MOSFET switches.

[0135] Example 11:

[0136] See Figures 1 to 12 A magnetic induction current sharing parallel SiC MOSFET pulse generator includes: a control signal generation module, an opto-isolation drive module, a solid-state switch drive module, a magnetic induction current sharing module, a Marx pulse generator output module, and a load.

[0137] The control signal generation module is used to generate solid-state switch control signals.

[0138] The opto-isolation drive module is used to eliminate the high-potential floating of solid-state switches.

[0139] After receiving the solid-state switch control signal, the solid-state switch driver module controls the on and off of each switch in the Marx pulse generator output module, as well as the on and off time.

[0140] The magnetic induction current sharing module is used to eliminate uneven current between solid-state switches.

[0141] The Marx pulse generator output module is used to generate pulse signals and input the pulse signals into the load.

[0142] The circuit topology of the pulse generator is shown below:

[0143] Remember the power supply The end containing the positive electrode is called terminal I, and the end containing the negative electrode is called terminal J. Terminal J is grounded.

[0144] The I terminal is connected to a diode. anode, diode Cathode connection capacitor Then connect to the J end.

[0145] The diode Cathode connected magnetic induction current sharing parallel switch module Connected to diode cathode, diode The anode is connected to the J terminal.

[0146] The magnetic induction current sharing parallel switch module Including magnetic induction coupling coils Solid-state switches Solid-state switches , where i = 1, 2, ..., n, and n is a positive integer.

[0147] Magnetic induction coupling coil It includes a first transmission line, a second transmission line, and a magnetic ring.

[0148] The first and second transmission lines are symmetrically wound around both sides of the magnetic ring.

[0149] Describe the magnetic induction coupling coil One end of the first transmission line is One end, the other end is One end of the second transmission line is... One end, the other end is end.

[0150] The Terminal connection diode The cathode, the Terminal connection diode The cathode.

[0151] The Terminal connection solid-state switch drain, solid-state switch The source is connected to the diode. The cathode.

[0152] The Terminal connection solid-state switch drain, solid-state switch The source is connected to the diode. The cathode.

[0153] The diode Cathode connection capacitor Connected to diode The anode.

[0154] The diode Anode-connected diode The cathode, where k = 2, 3, ..., n.

[0155] The diode Anode-connected diode The cathode.

[0156] The diode Cathode connection load Connected to diode The anode.

[0157] The various modules of this invention patent are as follows: Figure 1 As shown.

[0158] The Marx main circuit topology is as follows: (Magnetic induction current sharing parallel switch) Figure 2 As shown.

[0159] Example 12:

[0160] A pulse generator based on magnetic induction current sharing parallel SiC MOSFETs is described in Embodiment 11. Furthermore, the pulse generator also includes a host computer.

[0161] The host computer generates circuit parameters and transmits them to the control signal generation module, which then generates solid-state switch control signals.

[0162] Example 13:

[0163] A pulse generator based on magnetic induction current sharing and parallel SiC MOSFETs, the main technical contents of which are described in any one of Embodiments 11 to 12, further... Figure 3 It is the Marx equivalent circuit of a magnetic induction current-sharing parallel switch, when a solid-state switch... Solid-state switches When the circuit is turned on, the branch currents in the first and second transmission lines flow into two coupled coils with the same number of turns on the magnetic core, generating magnetic fluxes in opposite directions in the magnetic circuit.

[0164] Example 14:

[0165] A pulse generator based on magnetic induction current sharing in parallel SiC MOSFETs is described, with key technical details provided in any of embodiments 11 to 13. Further, assuming completely identical devices and perfectly symmetrical power circuits, the currents in the two parallel branches are equal, generating magnetic fluxes of opposite directions and equal magnitudes in the magnetic core. The combined magnetic flux is zero and has no effect on the branch currents. However, due to inconsistencies in device parameters and circuit parasitic parameters, the currents in the two branches deviate. The current difference between the two branches generates magnetic flux in the magnetic core. According to Faraday's law of electromagnetic induction, an electromotive force will be induced in the primary coil. The secondary coil induces an electromotive force. The electromotive force drives the unbalanced current to remain zero. As shown below:

[0166] (1)

[0167] In the formula, The magnetizing inductance of the magnetically coupled coil. The current difference within the coil is denoted by t, where t is time.

[0168] Therefore, current balance between the two switching branches can be achieved. Essentially, the magnetic induction coupling coil uses magnetic flux as a medium to transmit current from one branch to another. Under ideal conditions, it can eliminate unbalanced current without losing energy.

[0169] Example 15:

[0170] A pulse generator based on magnetic induction current sharing and parallel SiC MOSFETs, the main technical contents of which are described in any one of Embodiments 11 to 14, further... Figure 4 This is the physical model of a magnetically coupled coil, which, according to Ampere's circuital law,

[0171] (2)

[0172] In the formula, n is the number of turns of the coil. i is the coil current. H is the magnetic field strength. D is the equivalent diameter of the coil. , These are the outer and inner diameters of the magnetic core, respectively.

[0173] because

[0174] (3)

[0175] The magnetizing inductance of the magnetic induction coupling coil of the magnetic induction current sharing parallel switch module and leakage As shown below:

[0176] (4)

[0177] In the formula, This represents the number of turns in the coil. , These are the outer diameter and inner diameter of the magnetic core, respectively. This represents the current difference within the coil. denoted as ρ, where ρ is the relative permeability of the magnetic core. The permeability of free space, . This is the current flowing through the coil. This is the coil length.

[0178] Among them, the magnetic flux density in the magnetic core As shown below:

[0179] (5)

[0180] In the formula, is the magnetic permeability. denoted as , where is the magnetic field strength in the magnetic core. This represents the current within the first transmission line. This refers to the current within the second transmission line.

[0181] Leakage flux density in air As shown below:

[0182] (6)

[0183] In the formula, The magnetic field strength in the air.

[0184] The cross-sectional area S of the magnetic core is shown below:

[0185] (7)

[0186] In the formula, h is the height of the magnetic core.

[0187] Example 16:

[0188] A pulse generator based on magnetic induction current sharing and parallel SiC MOSFETs, the main technical contents of which are described in any one of Embodiments 11 to 15, further... Figure 5This is the equivalent circuit model of magnetic induction current sharing during the dynamic process of the switch. The SiC MOSFET is equivalent to a controlled source and a variable resistor model, and the branch current satisfies:

[0189] (8)

[0190] in, , ,like , , , , The equation can be simplified to:

[0191] (9)

[0192] Meanwhile, because MOSFETs have a faster turn-on speed, It can be approximated as:

[0193] (10)

[0194] in, For the current across the load resistor after the MOSFET is fully turned on, the equation, after Laplace transformation, yields:

[0195] (11)

[0196] The solid-state switch Solid-state switches The dynamic response time of the unbalanced current during the transient process of conduction. As shown below:

[0197] (12)

[0198] In the formula, The magnetizing inductance of the magnetically coupled coil. The leakage inductance of the magnetically coupled coil. solid-state switch The drain parasitic inductance, solid-state switch The source parasitic inductance, solid-state switch The resistance between the drain and the source This refers to the variable resistor during the dynamic switching process. Typically, the value is large, in the MΩ range, so the unbalanced current during the switching dynamic process can be effectively suppressed in a very short time.

[0199] Example 17:

[0200] A pulse generator based on magnetic induction current sharing and parallel SiC MOSFETs, the main technical contents of which are described in any one of Embodiments 11 to 16, further... Figure 6 This is the equivalent circuit model of the magnetic induction current sharing in the switching branch after the switch is fully turned on. At this point, the SiCMOSFET can be equivalent to an on-resistor. The transient unbalanced current of the switch has been effectively suppressed. However, due to the switch on-resistance There are differences. As the pulse width increases, the static unbalanced current in the switching branch gradually increases. At this time, the current sharing principle of the magnetic induction coupling coil is as follows:

[0201] From the branch current equation,

[0202] (13)

[0203] It can be known that:

[0204] (14)

[0205] Then we can obtain:

[0206] (15)

[0207] At this point, the branch current satisfies the equation:

[0208] (16)

[0209] like Equation (16) can be simplified to:

[0210] (17)

[0211] After the Laplace transform, it can be represented as:

[0212] (18)

[0213] The solid-state switch Solid-state switches After full conduction, the magnetizing inductor For unbalanced current The time constant for the inhibitory effect As shown below:

[0214] (19)

[0215] In the formula, solid-state switch The on-resistance.

[0216] Example 18:

[0217] A pulse generator based on magnetic induction current sharing parallel SiC MOSFETs is provided. The main technical contents are described in any one of embodiments 11 to 17. Furthermore, the pulse width range of the magnetic induction coupling coil for suppressing unbalanced current stress between solid-state switches is 50ns-1000ns.

[0218] Example 19:

[0219] A pulse generator based on magnetic induction current sharing parallel SiC MOSFETs is provided. The main technical contents are described in any one of Embodiments 11 to 18. Furthermore, the pulse output voltage amplitude, pulse width, and pulse frequency of the pulse generator are all adjustable.

[0220] The voltage amplitude range of the pulse generator output is 500V-5kV.

[0221] The pulse width output by the pulse generator ranges from 50ns to 1000ns.

[0222] The pulse generator outputs pulses in the range of 1 Hz - 1 kHz.

[0223] Example 20:

[0224] A pulse generator based on magnetic induction current sharing parallel SiC MOSFETs, the main technical contents of which are described in any one of embodiments 11 to 19, further wherein the solid-state switch Solid-state switches Both use MOSFET switches.

[0225] Example 21:

[0226] See Figures 1 to 6 A pulse generator based on magnetic induction current sharing parallel SiC MOSFETs, the main technical contents of which include:

[0227] The various modules of this invention patent are as follows: Figure 1 As shown.

[0228] The Marx main circuit topology is as follows: (Magnetic induction current sharing parallel switch) Figure 2 As shown:

[0229] Figure 3This is the Marx equivalent circuit of a parallel current-sharing switch with magnetic induction. When the parallel SiC MOSFETs start conducting, the currents in the two SiC MOSFET branches flow into two coupled coils with the same number of turns on the common magnetic core, generating magnetic fluxes in opposite directions in the magnetic circuit. Assuming the devices are perfectly identical and the power loop is perfectly symmetrical, the currents in the two parallel branches are equal, generating magnetic fluxes in opposite directions and of equal magnitude in the magnetic core, while the resultant magnetic flux is zero and has no effect on the branch currents. However, due to inconsistencies in device parameters and circuit parasitic parameters, there is a deviation in the currents of the two branches. This current difference generates magnetic flux in the magnetic core, and according to Faraday's law of electromagnetic induction, the primary coil will induce an electromotive force. The secondary coil induces an electromotive force. , This electromotive force will drive the unbalanced current to remain zero, thus achieving current balance between the two switching branches. Essentially, the magnetically coupled coil uses magnetic flux as a medium to transmit current from one branch to another, ideally eliminating unbalanced current without energy loss.

[0230] Figure 4 This is the physical model of a magnetically coupled coil, which, according to Ampere's circuital law,

[0231] (1)

[0232] In the formula, n is the number of turns of the coil. i is the coil current. H is the magnetic field strength. D is the equivalent diameter of the coil. , These are the outer and inner diameters of the magnetic core, respectively.

[0233] Magnetic flux density in the core and leakage magnetic flux density in air It can be represented as:

[0234]

[0235]

[0236] In the formula, Vacuum permeability , Let l be the relative permeability of the magnetic core and l be the length of the coil.

[0237] because

[0238]

[0239] Where S is the cross-sectional area of ​​the magnetic core. h is the height of the magnetic core.

[0240] The magnetizing inductance of the magnetically coupled coil can then be obtained. and leakage for:

[0241]

[0242] Figure 5 This is the equivalent circuit model of magnetic induction current sharing during the dynamic process of the switch. The SiC MOSFET is equivalent to a controlled source and a variable resistor model, and the branch current satisfies:

[0243]

[0244] in, , ,like , , , , The equation can be simplified to:

[0245]

[0246] Meanwhile, because MOSFETs have a faster turn-on speed, It can be approximated as:

[0247]

[0248] in, For the current across the load resistor after the MOSFET is fully turned on, the equation, after Laplace transformation, yields:

[0249]

[0250] It can be seen that during the switching transient process, the dynamic response time of the unbalanced current is:

[0251]

[0252] During the switching dynamic process, the variable resistor Typically, the value is large, in the MΩ range, so the unbalanced current during the switching dynamic process can be effectively suppressed in a very short time.

[0253] Figure 6 This is the equivalent circuit model of the magnetic induction current sharing in the switching branch after the switch is fully turned on. At this point, the SiC MOSFET can be equivalent to an on-resistor. The transient unbalanced current of the switch has been effectively suppressed. However, due to the switch on-resistance There are differences. As the pulse width increases, the static unbalanced current in the switching branch gradually increases. At this time, the current sharing principle of the magnetic induction coupling coil is as follows:

[0254] From the branch current equation,

[0255]

[0256] It can be known that:

[0257]

[0258] Then we can obtain:

[0259]

[0260] At this point, the branch current satisfies the equation:

[0261]

[0262] like Equation (14) can be simplified to:

[0263]

[0264] After the Laplace transform, it can be represented as:

[0265] (16)

[0266] Therefore, it can be known that when the switch is fully turned on, the magnetizing inductance... For unbalanced current The time constant for the inhibitory effect is:

[0267] (17)

[0268] Example 22:

[0269] See Figures 1 to 8 A pulse generator based on magnetic induction current sharing parallel SiC MOSFETs, the main technical contents of which include:

[0270] To fully verify the feasibility of the magnetic induction current sharing method based on coupled inductors proposed in this invention in suppressing transient and static unbalanced currents in parallel SiC MOSFETs, a simulation model based on PSpice software was built. Figure 2 Marx simulation circuits, such as Figure 7As shown in Table 1, the parameters of the PSpice simulation model are shown in Table 1. In the simulation circuit, small resistors of different values ​​are connected in series with the source of the SiCMOSFET in different branches. The difference in on-resistance and parasitic resistance of the main discharge circuit, representing device parameters, is reflected in the drain series inductance of the SiC MOSFET. This represents a discrepancy between the parasitic inductance parameters of the switching device and the main circuit. Different values ​​of drive resistors are connected in series with the gate of the SiC MOSFET. This represents the difference in parasitic parameters of the switch drive circuit.

[0271] The Marx simulation output results for a single-stage magnetic induction current sharing system based on coupled inductors are as follows: Figure 8 As shown in the figure, the simulation circuit is set to a DC input of 800V and a pulse width of 200ns. It can be seen that when the parameters of the switching devices in different branches are dispersed or the parasitic parameters of the loop lack consistency (i.e., when the parasitic resistance and stray inductance of the simulated parallel MOSFET branches are inconsistent), the parallel SiC MOSFETs exhibit current imbalance during both transient and static conduction processes without current sharing measures.

[0272] Table 1 Simulation Parameters

[0273]

[0274] After adopting magnetic induction current sharing, the unbalanced current of the switch in both transient and static processes is effectively suppressed.

[0275] Example 23:

[0276] See Figures 1 to 12 A pulse generator based on magnetic induction current sharing parallel SiC MOSFETs, the main technical contents of which include:

[0277] To verify the feasibility of this invention, a corresponding experimental prototype was developed and a testing facility was constructed. Figure 9 The test platform shown has the top PCB board of the Marx pulse source as follows: Figure 10 As shown in Table 2, the main experimental parameters are as follows.

[0278] Table 2 Main experimental parameters

[0279]

[0280] Figure 11 These are the test results of an eight-stage Marx prototype. The figure shows that without current sharing measures, significant unbalanced currents appeared between the parallel switches under a 200ns pulse width. However, after adding magnetic induction current sharing measures, a better current sharing effect was achieved. Figure 12The output waveform of the Marx prototype with variable pulse width is shown, ranging from 50 to 1000 ns. The pulse voltage output is 5 kV, and the maximum pulse current output is 50 A. The prototype experimental results verify the effective current sharing capability of the magnetic induction current sharing method and the stable output capability of the pulse source. While ensuring the current stress balance of the parallel switch branch, it increases the output of the pulse source with greater current and power.

[0281] In summary, addressing the challenge of traditional Marx generators where output current and power are limited by the rated current of the switching devices used, hindering the achievement of higher current and power outputs, this invention develops a pulse generator based on magnetic induction current sharing and parallel SiC MOSFETs. By employing magnetic induction current sharing technology to suppress transient and static unbalanced currents during pulse generation, the problem of uneven current distribution between parallel switching devices is solved, enabling reliable and stable high-current output from the Marx generator. The pulse generator adopts a modular design, allowing for flexible adjustment of its output amplitude, pulse width, and pulse frequency.

Claims

1. A pulse generator based on magnetic induction current sharing in parallel SiC MOSFETs, characterized in that, include: The control signal generating module, the photoelectric isolation driving module, the solid-state switch driving module, the n magnetic induction current-sharing parallel switch modules , a Marx pulse generator output module and a load, wherein n is a positive integer; The control signal generation module is used to generate solid-state switch control signals; The opto-isolation drive module is used to eliminate the high-potential floating of the solid-state switch; After receiving the solid-state switch control signal, the solid-state switch driver module controls the on and off of each switch in the Marx pulse generator output module, as well as the on and off time. The magnetic induction current sharing parallel switch module Used to eliminate uneven current between solid-state switches; The Marx pulse generator output module is used to generate pulse signals and input the pulse signals into the load. The circuit topology of the pulse generator is shown below: Remember the power supply The end containing the positive electrode is called terminal I, and the end containing the negative electrode is called terminal J. Terminal J is grounded. The I terminal is connected to a diode. anode, diode Cathode connection capacitor Then connect to the J end; The diode Cathode connected magnetic induction current sharing parallel switch module Connected to diode cathode, diode The anode is connected to the J terminal; The magnetic induction current sharing parallel switch module Including magnetic induction coupling coils Solid-state switches Solid-state switches , where i = 1, 2, ..., n; Magnetic induction coupling coil Includes a first transmission line, a second transmission line, and a magnetic ring; The first and second transmission lines are symmetrically wound around both sides of the magnetic ring; Describe the magnetic induction coupling coil One end of the first transmission line is One end, the other end is One end of the second transmission line is One end, the other end is end; The Terminal connection diode The cathode, the Terminal connection diode The cathode; The Terminal connection solid-state switch drain, solid-state switch The source is connected to the diode. The cathode; The Terminal connection solid-state switch drain, solid-state switch The source is connected to the diode. The cathode; The diode Cathode connection capacitor Connected to diode The anode; The diode Anode-connected diode The cathode, where k = 2, 3, ..., n; The diode Anode-connected diode The cathode; The diode Cathode connection load Connected to diode The anode.

2. The pulse generator based on magnetic induction current sharing in parallel SiC MOSFETs according to claim 1, characterized in that, The pulse generator also includes a host computer; The host computer generates circuit parameters and transmits them to the control signal generation module, which then generates solid-state switch control signals.

3. A pulse generator based on magnetic induction current sharing in parallel SiC MOSFETs according to claim 1, characterized in that, When solid-state switch Solid-state switches When the circuit is turned on, the branch currents in the first and second transmission lines flow into two coupled coils with the same number of turns on the magnetic core, generating magnetic fluxes in opposite directions in the magnetic circuit.

4. A pulse generator based on magnetic induction current sharing in parallel SiC MOSFETs according to claim 3, characterized in that, The current difference between the two branches generates a magnetic flux in the magnetic core, which induces an electromotive force in the primary coil. The secondary coil induces an electromotive force. The electromotive force drives the unbalanced current to remain zero. As shown below: （1） In the formula, The magnetizing inductance of the magnetically coupled coil. The difference in current within the coil; t represents time.

5. A pulse generator based on magnetic induction current sharing in parallel SiC MOSFETs according to claim 1, characterized in that, The magnetizing inductance of the magnetic induction coupling coil of the magnetic induction current sharing parallel switch module and leakage As shown below: （2） In the formula, This refers to the number of coil turns. , These are the outer diameter and inner diameter of the magnetic core, respectively. The difference in current within the coil; The relative permeability of the magnetic core; The vacuum permeability; The current flowing through the coil; The length of the coil; Among them, the magnetic flux density in the magnetic core As shown below: （3） In the formula, Permeability; The magnetic field strength in the magnetic core; This refers to the current within the first transmission line; This refers to the current within the second transmission line; Leakage flux density in air As shown below: （4） In the formula, The strength of the magnetic field in the air; The cross-sectional area S of the magnetic core is shown below: （5） In the formula, h is the height of the magnetic core.

6. A pulse generator based on magnetic induction current sharing in parallel SiC MOSFETs according to claim 4, characterized in that, The solid-state switch Solid-state switches The dynamic response time of the unbalanced current during the transient process of conduction. As shown below: （6） In the formula, The magnetizing inductance of the magnetically coupled coil. The leakage inductance of the magnetically coupled coil. solid-state switch The drain parasitic inductance, solid-state switch The source parasitic inductance, solid-state switch The resistance between the drain and the source This is the variable resistor during the dynamic switching process.

7. A pulse generator based on magnetic induction current sharing in parallel SiC MOSFETs according to claim 4, characterized in that, The solid-state switch Solid-state switches After full conduction, the magnetizing inductor For unbalanced current The time constant for the inhibitory effect As shown below: （7） In the formula, solid-state switch The on-resistance.

8. A pulse generator based on magnetic induction current sharing in parallel SiC MOSFETs according to claim 1, characterized in that, The pulse width range for the magnetic induction coupling coil to suppress unbalanced current stress between solid-state switches is 50ns-1000ns.

9. A pulse generator based on magnetic induction current sharing in parallel SiC MOSFETs according to claim 1, characterized in that, The pulse output voltage amplitude, pulse width, and pulse frequency of the pulse generator are all adjustable. The voltage amplitude range of the pulse generator output is 500V-5kV; The pulse width output by the pulse generator is in the range of 50ns-1000ns; The pulse generator outputs pulses in the range of 1Hz - 1kHz.

10. A pulse generator based on magnetic induction current sharing in parallel SiC MOSFETs according to claim 1, characterized in that, The solid-state switch Solid-state switches Both use MOSFET switches.

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