A high voltage switching assembly based on series connected SiC MOSFETs

Abstract

The application discloses a high-voltage switch assembly based on SiC MOSFET series connection, which comprises a magnetic isolation driving module; when the magnetic isolation driving module works, a primary winding receives an external driving signal; a magnetic core and a magnetic ring generate a control signal under the action of the external driving signal, and the control signal is transmitted to the magnetic isolation driving module through a secondary winding; the magnetic isolation driving module isolates control signals of different switches, and under the action of the control signals, the series connection switches synchronously act to output a high-voltage pulse. The application manufactures a set of high-voltage switch assembly, and the maximum safe working voltage can reach 60kV, and the highest withstand voltage is 100kV.

Description

TECHNICAL FIELD

[0001] The application relates to the field of SiC high-voltage switch pulse modulators, in particular to a SiC MOSFET series high-voltage switch assembly. BACKGROUND

[0002] The high-frequency, high-voltage, high-temperature resistance, fast switching speed and low loss of the silicon carbide device make the efficiency and power density of the all-solid-state pulse power system advance in a higher direction. The excellent characteristics of the silicon carbide device need to be perfectly exhibited through packaging integration, reliable driving of a switch driver and optimized circuit structure.

[0003] The traditional pulse generation circuit usually uses a scheme of multiplying voltage by using dozens of low-voltage devices, and the driving mode is based on full separation driving, which means that each semiconductor device needs an independent driving circuit and an isolated power supply.

[0004] Since the isolation capability of the power supply DC-DC restricts the voltage level of the pulse generator, the cascade structure may be the most ideal and simplest solution. However, the voltage resistance capability of a single device is limited, and still cannot meet the demand of people for high-voltage switch devices, therefore, there is an urgent need for a pulse generator capable of realizing high-voltage level. SUMMARY

[0005] The application aims to provide a SiC MOSFET series high-voltage switch assembly, which comprises a magnetic isolation driving module;

[0006] The magnetic isolation driving module comprises n cascaded magnetic isolation driving circuits; an integer n is greater than or equal to 1;

[0007] Each magnetic isolation driving circuit comprises at least a plurality of switching tubes, a plurality of resistors and a magnetic ring;

[0008] Each magnetic ring is wound with a secondary winding;

[0009] The n magnetic rings are sleeved on the same magnetic core; the magnetic core is internally arranged with a primary winding, and the primary winding is led out from both ends of the magnetic core;

[0010] The circuit topology of the i-th magnetic isolation driving circuit is as follows:

[0011] Let the two ends of the secondary winding wound on the i-th magnetic ring be Bi1 end and Bi2 end respectively;

[0012] One end of the resistor Ri-1 is connected with the Bi1 end of the secondary winding, and the other end is connected with the gate of the switching tube Si-1; the source of the switching tube Si-1 is connected with the Bi2 end of the secondary winding, and the drain is connected with the drain of the switching tube S(i+1)-3 of the i+1-th magnetic isolation driving module;

[0013] The source of the switch tube Si-2 is connected to the Bi1 end of the secondary winding, and the drain is connected to the gate of the switch tube Si-3 after being connected to the resistor Rgi; the drain of the switch tube Si-2 is connected to the drain of the switch tube S(i+1)-3 after being connected to the resistor Rgi and the bidirectional voltage stabilizing diode Zi;

[0014] The drain of the switch tube Si-2 is connected to the drain of the switch tube S(i+1)-3 after being connected to the resistor Rgi and the bidirectional voltage stabilizing diode Zi; the gate of the switch tube Si-2 is connected to the drain of the switch tube S(i+1)-3 after being connected to the resistor Rgi-2;

[0015] The source of the switch tube Si-3 is connected to the drain of the switch tube S(i+1)-3 after being connected to the resistor Rli;

[0016] When the magnetic isolation driving module works, the primary winding receives an external driving signal;

[0017] The magnetic core and the magnetic ring generate a control signal under the action of the external driving signal, and the control signal is transmitted to the magnetic isolation driving module through the secondary winding;

[0018] The magnetic isolation driving module isolates the control signals of different switches, and under the action of the control signal, the series switches are synchronously actuated to output a high-voltage pulse.

[0019] Further, the switch tube Si-1, the switch tube Si-2 and the switch tube Si-3 each comprise a MOS tube and a body diode connected in parallel with the MOS tube.

[0020] Further, the resistor Rli is used for realizing overcurrent protection of the switch tube. The resistor Rli is a thick-film non-inductive resistor.

[0021] Further, the control signal comprises a first control signal and a second control signal.

[0022] When the secondary winding transmits the first control signal to the magnetic isolation driving module, the magnetic isolation driving module is in a charging state;

[0023] When the secondary winding transmits the second control signal to the magnetic isolation driving module, the magnetic isolation driving module is in a discharging state.

[0024] Further, when the magnetic isolation driving module is in the charging state, the switch Si-1 is turned on, the current passes through the body diode of Si-2, and then a closed loop is formed, the capacitor Cgi starts to be charged, until the voltage across the capacitor Cgi reaches +V m , the gate-source voltage of the switch Si-3 reaches +V m , and the switch Si-3 is turned on;

[0025] Further, when the magnetic isolation driving module is in the discharging state, the switch Si-2 is turned on, the current passes through the body diode of the switch Si-1, and then a closed loop is formed; the capacitor Cgi starts to discharge, and then the capacitor Cgi starts to charge in the opposite direction until the voltage across the capacitor Cgi reaches -V m , the drain-source voltage of the switch Si-3 becomes -V m , and the switch Si-3 is turned off.

[0026] Further, the conversion time of the state of the magnetic isolation driving module from the charging state to the discharging state is the first signal dead time, and the conversion time from the discharging state to the charging state is the second signal dead time.

[0027] In the first signal dead time, the switches Si-1 and Si-2 are turned off; the charge of the capacitor Cgi has no discharge path, and the voltage across the capacitor Cgi is still +V m , and the switch Si-3 is continuously turned on.

[0028] In the second signal dead time, the switches Si-1 and Si-2 are turned off; the charge of the capacitor Cgi has no discharge path, and the voltage across the capacitor Cgi is still -V m , and the switch Si-3 is continuously turned off.

[0029] Further, the magnetic isolation driving module further comprises a voltage equalization circuit module.

[0030] The voltage equalization circuit module comprises voltage equalization resistors Rs and capacitors Cs connected in parallel at the drain and source of the switch, respectively.

[0031] Further, the primary winding adopts a direct-current high-voltage insulated wire.

[0032] The technical effect of the present application is self-evident. The present application provides a structure based on a compact high-voltage MOSFET module, which can be connected in series with any number of devices.

[0033] The present application adopts a 3D stacked series switch assembly scheme, utilizes the mutual inductance cancellation principle, and reduces the overall parasitic inductance, which is reduced by about 84.1% compared with a linear series.

[0034] The overcurrent protection scheme used in the present application has a faster overcurrent response speed compared with conventional overcurrent protection schemes, and improves the surge current resistance of the switch.

[0035] The present application ensures the voltage level while ensuring that each level of switch can normally turn on, and the delay between each level of switch is short.

[0036] The present application manufactures a set of high-voltage switch assemblies, and the maximum safe working voltage can reach 60kV, and the maximum withstand voltage is 100kV. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 (a)-(d) are schematic diagrams of magnetic isolation circuit;

[0038] Figure 2 is a driving circuit diagram of a series core magnetic ring;

[0039] Figure 3 is a voltage equalization circuit;

[0040] Figure 4 is a over-current protection principle.

[0041] Figure 5 is a schematic diagram of a 3D stacked high-voltage switch assembly. DETAILED DESCRIPTION

[0042] The application will be further described below in conjunction with the embodiments, but should not be understood as limiting the above-mentioned subject matter of the application to the following embodiments. Various substitutions and modifications can be made according to ordinary technical knowledge and conventional means in the art without departing from the above-mentioned technical idea of the application, and all should be included in the protection scope of the application.

[0043] Example 1:

[0044] Referring to Figures 1 to 5 A high-voltage switch assembly based on SiC MOSFET series connection includes a magnetic isolation driving module;

[0045] The magnetic isolation driving module includes n cascaded magnetic isolation driving circuits; an integer n≥1;

[0046] Each magnetic isolation driving circuit includes at least a plurality of switching tubes, a plurality of resistors and a magnetic ring;

[0047] Each magnetic ring is wound with a secondary winding;

[0048] The n magnetic rings are sleeved on the same magnetic core; the magnetic core is internally arranged with a primary winding, and the primary winding is led out from both ends of the magnetic core;

[0049] The circuit topology of the i-th magnetic isolation driving circuit is as follows:

[0050] Let the two ends of the secondary winding wound on the i-th magnetic ring be Bi1 end and Bi2 end, respectively;

[0051] One end of the resistor Ri-1 is connected to the Bi1 end of the secondary winding, and the other end is connected to the gate of the switching tube Si-1; the source of the switching tube Si-1 is connected to the Bi2 end of the secondary winding, and the drain is connected to the drain of the switching tube S(i+1)-3 of the i+1-th magnetic isolation driving module;

[0052] The source of the switch Si-2 is connected to the Bi1 terminal of the secondary winding, and the drain is connected in series with the resistor Rgi and then to the gate of the switch Si-3; the drain of the switch Si-2 is connected in series with the capacitor Cgi and then to the drain of the switch S(i+1)-3;

[0053] The drain of the switch tube Si-2 is connected in series with a resistor Rgi and a bidirectional voltage regulator diode Zi, and then connected to the drain of the switch tube S(i+1)-3; the gate of the switch tube Si-2 is connected in series with a resistor Ri-2, and then connected to the drain of the switch tube S(i+1)-3;

[0054] The source of the switch tube Si-3 is connected in series with the resistor Rli and then connected to the drain of the switch tube S(i+1)-3;

[0055] When the magnetic isolation drive module is working, the primary winding receives the external drive signal;

[0056] The magnetic core and the magnetic ring generate a control signal under the action of an external driving signal, and transmit the control signal to the magnetic isolation driving module through the secondary winding;

[0057] The magnetic isolation drive module isolates the control signals of different switches and, under the action of the control signals, enables the series switches to operate synchronously and output high-voltage pulses.

[0058] The resistor Rli is used to implement overcurrent protection for the switch tube. The resistor Rli is a thick film non-inductive resistor.

[0059] The switch tube Si-1, the switch tube Si-2, and the switch tube Si-3 each include a MOS tube and a body diode connected in parallel with the MOS tube.

[0060] The control signal includes a first control signal and a second control signal;

[0061] When the secondary winding transmits the first control signal to the magnetic isolation driving module, the magnetic isolation driving module is in a charging state;

[0062] When the secondary winding transmits the second control signal to the magnetic isolation driving module, the magnetic isolation driving module is in a discharging state.

[0063] When the magnetic isolation drive module is in the charging state, the switch Si-1 is turned on, and the current passes through the body diode of Si-2, thereby forming a closed loop (such as Figure 1 As shown in (a), the specific circuit is marked by the dotted line with an arrow), the capacitor Cgi starts to charge until the voltage across the capacitor Cgi reaches +V m , the gate-source voltage of switch Si-3 reaches +V m , switch Si-3 is turned on;

[0064] When the magnetic isolation drive module is in the discharge state, the switch Si-2 is turned on, and the current passes through the body diode of the switch Si-1, thereby forming a closed loop (such as Figure 1 As shown in (c), the specific loop is marked by the dotted line with an arrow); the capacitor Cgi begins to discharge, and then the capacitor Cgi begins to charge in the reverse direction until the voltage across the capacitor Cgi reaches -V m , the drain-source voltage of switch Si-3 becomes -V m , switch Si-3 is turned off.

[0065] The conversion time of the magnetic isolation drive module from the charging state to the discharging state is the first signal dead time, and the conversion time from the discharging state to the charging state is the second signal dead time;

[0066] During the first signal dead zone, switches Si-1 and Si-2 are turned off; the charge of capacitor Cgi has no discharge path, and the voltage across both ends remains +V m , switch Si-3 is continuously turned on.

[0067] During the second signal dead time, switches Si-1 and Si-2 are turned off; the charge of capacitor Cgi has no discharge path, and the voltage across both ends remains -V m , switch Si-3 is continuously turned off.

[0068] The magnetic isolation driving module also includes a voltage equalization circuit module;

[0069] The voltage balancing circuit module includes a voltage balancing resistor Rs and a capacitor Cs respectively connected in parallel to the drain and source ends of the switch.

[0070] The primary winding adopts a DC high voltage insulated wire.

[0071] The driving circuit designed in the present invention is mainly applied to 3.3kV grade SiC MOSFET.

[0072] The present invention ensures that the switches at each level can be turned on normally while ensuring the voltage level, and the delay between switches at each level is short. The gate capacitance value of each level is equal, both 10nF.

[0073] The series static voltage-equalizing resistor is a 600kΩ high-voltage 4kV resistor.

[0074] The capacitor selected for series dynamic voltage balancing is a 45nF high voltage 6kV capacitor.

[0075] The present invention adopts a 0.25Ω, 10W thick film non-inductive resistor for overcurrent protection of the high voltage switch.

[0076] Example 2:

[0077] A SiC MOSFET series high voltage switching module, the contents are as follows:

[0078] Magnetic isolation drive module:

[0079] Considering that in the process of opening and closing, the switching speed, switching loss and switching stress of the device are largely dependent on di / dt, dv / dt and gate loop current, and need to be electrically isolated, so the magnetic isolation method is adopted. The drive circuit is shown in Figure 1 , the drive process is divided into:

[0080] (a) When the positive control signal is transmitted to the secondary side of the magnetic core, S 1-1 is turned on, the current passes through S 1-2 body diode to form a closed loop, and the capacitor C starts to charge. When the capacitor C is charged to +V m , the gate-source voltage of the switch S 1-3 rises to +V m , and the switch S 1-3 is turned on.

[0081] (b) When the signal dead zone comes, S 1-1 and S 1-2 are both in the off state, the charge of the capacitor C has no discharge path, and the potential +V m is maintained, and the switch S 1-3 remains on.

[0082] (c) When the negative control signal is transmitted to the secondary side of the magnetic core, S 1-2 is turned on, the current passes through S 1-1 body diode to form a closed loop, and the original charge in the capacitor C starts to release and then charges in the opposite direction to -V m , the drain-source voltage of the switch S 1-3 becomes -V m , and the switch S 1-3 is turned off.

[0083] (d) Similar to stage (a), S1-1 and S1-2 are both in the off state, the charge of the capacitor C has no discharge path, and the potential -V m is maintained, and the switch S S1-3 remains off.

[0084] Series core magnetic ring drive module:

[0085] A high insulation grade cable is used as the primary winding of the magnetic isolation drive, the cable passes through the inside of the magnetic core, and the insulation grade of the cable will also limit the number of series modules and the final output voltage level. In this design, a 0.8mm diameter, 100kV insulation strength DC high voltage wire is used, and a total of 30 drive modules are used in this design. The series core magnetic ring drive schematic is shown in Figure 2 .

[0086] Static voltage equalization buffer circuit:

[0087] Static voltage equalization requires voltage equalization resistance, Figure 3 As shown in the MOSFET series circuit, if the voltage equalization resistance R is much smaller than the drain resistance of the series elements, the voltage between each element can reach the purpose of static voltage equalization after selecting the same resistance R. After connecting the capacitor C in parallel at both ends of the switch, the series circuit can achieve the purpose of dynamic voltage equalization, because the voltage of the capacitor cannot change suddenly, and the current of the switch that is turned off first is transferred to the capacitor C, causing the voltage at both ends of the switch to slowly rise, and then the switches in the series circuit are in a dynamic voltage equalization operating state.

[0088] Module superposition method:

[0089] There are a large number of parasitic inductances in the PCB circuit board, and the existence of parasitic inductance has a great influence on the output voltage of the high-voltage switch assembly. Under the premise of ensuring insulation, a 3D stacked series switch assembly scheme is proposed. This scheme uses the principle of mutual inductance cancellation to reduce the overall parasitic inductance, and compared with the linear series, the inductance is reduced by about 84.1%.

[0090] Overcurrent protection design:

[0091] According to KVL, the module loop equation can be written as follows

[0092] V m =V gs +V R +V Rg (1)

[0093] V R =i2×R l (2)

[0094] V Rg =i1×R gl (3)

[0095] i1 is the current flowing through the switch gate source, which has a lower value. The voltage of the gate resistor is almost zero. Equation (1) is converted to equation (4)

[0096] Vm=V gs +R1×i2 (4)

[0097] When overcurrent occurs due to load short circuit, i2 increases, V R also increases accordingly. V m is a fixed value, and Vgs will decrease. V th is the threshold voltage of the switch, when V gs gradually decreases, the switch will enter the saturation amplification zone, and the on-resistance will increase, limiting the rise of short-circuit current.

[0098] The maximum safe working voltage can reach 60kV and the highest withstand voltage is 100kV when 30 modules are connected in series.

[0099] Embodiment 3

[0100] A high-voltage switching assembly based on SiC MOSFET series connection comprises a magnetic isolation driving module;

[0101] The magnetic isolation driving module comprises n magnetic isolation driving circuits connected in series; the integer n is greater than or equal to 1;

[0102] Each magnetic isolation driving circuit comprises at least a plurality of switching tubes, a plurality of resistors and a magnetic ring;

[0103] Each magnetic ring is wound with a secondary winding;

[0104] The n magnetic rings are sleeved on the same magnetic core; the magnetic core is internally arranged with a primary winding, and the primary winding is led out from both ends of the magnetic core;

[0105] The circuit topology of the i-th magnetic isolation driving circuit is as follows:

[0106] Let the two ends of the secondary winding wound on the i-th magnetic ring be Bi1 end and Bi2 end respectively;

[0107] One end of the resistor Ri-1 is connected to the Bi1 end of the secondary winding, and the other end is connected to the gate of the switching tube Si-1; the source of the switching tube Si-1 is connected to the Bi2 end of the secondary winding, and the drain is connected to the drain of the switching tube S(i+1)-3 of the i+1-th magnetic isolation driving module;

[0108] The source of the switching tube Si-2 is connected to the Bi1 end of the secondary winding, and the drain is connected to the gate of the switching tube Si-3 after being connected in series with the resistor Rgi; the drain of the switching tube Si-2 is connected to the drain of the switching tube S(i+1)-3 after being connected in series with the capacitor Cgi;

[0109] The drain of the switching tube Si-2 is connected to the drain of the switching tube S(i+1)-3 after being connected in series with the resistor Rgi and the bidirectional voltage stabilizing diode Zi; the gate of the switching tube Si-2 is connected to the drain of the switching tube S(i+1)-3 after being connected in series with the resistor Ri-2;

[0110] The source of the switching tube Si-3 is connected to the drain of the switching tube S(i+1)-3 after being connected in series with the resistor Rli;

[0111] When the magnetic isolation driving module is working, the primary winding receives an external driving signal;

[0112] The magnetic core and the magnetic ring generate a control signal under the action of the external driving signal, and transmit the control signal to the magnetic isolation driving module through the secondary winding;

[0113] The magnetic isolation driving module isolates the control signals of different switches, and under the action of the control signals, the series switches are synchronously actuated to output a high-voltage pulse.

[0114] Embodiment 4:

[0115] The SiC MOSFET-based high-voltage switch assembly in series mainly includes the contents of Embodiment 3, wherein the switch tube Si-1, the switch tube Si-2, and the switch tube Si-3 each include a MOS tube and a body diode connected in parallel with the MOS tube.

[0116] Embodiment 5:

[0117] The SiC MOSFET-based high-voltage switch assembly in series mainly includes the contents of Embodiment 3, wherein the resistor Rli is used to realize overcurrent protection of the switch tube.

[0118] Embodiment 6:

[0119] The SiC MOSFET-based high-voltage switch assembly in series mainly includes the contents of Embodiment 3, wherein the control signal includes a first control signal and a second control signal.

[0120] When the secondary winding transmits the first control signal to the magnetic isolation driving module, the magnetic isolation driving module is in a charging state.

[0121] When the secondary winding transmits the second control signal to the magnetic isolation driving module, the magnetic isolation driving module is in a discharging state.

[0122] Embodiment 7:

[0123] The SiC MOSFET-based high-voltage switch assembly in series mainly includes the contents of Embodiment 3, wherein when the magnetic isolation driving module is in the charging state, the switch Si-1 is turned on, the current passes through the body diode of Si-2, thereby forming a closed loop, the capacitor Cgi starts to charge, until the voltage across the capacitor Cgi reaches +V m , the gate-source voltage of the switch Si-3 reaches +V m , and the switch Si-3 is turned on.

[0124] Embodiment 8:

[0125] The SiC MOSFET-based high-voltage switch assembly in series mainly includes the contents of Embodiment 3, wherein when the magnetic isolation driving module is in the discharging state, the switch Si-2 is turned on, the current passes through the body diode of the switch Si-1, thereby forming a closed loop; the capacitor Cgi starts to discharge, and then the capacitor Cgi starts to charge in the opposite direction, until the voltage across the capacitor Cgi reaches -V m , and the drain-source voltage of the switch Si-3 becomes -Vm Si-3 is off.

[0126] Embodiment 9:

[0127] A high-voltage switch assembly based on SiC MOSFET series, the main content is seen in embodiment 3, wherein the conversion time of the state of the magnetic isolation driving module from the charging state to the discharging state is the first signal dead time, and the conversion time from the discharging state to the charging state is the second signal dead time.

[0128] In the first signal dead time, switches Si-1 and Si-2 are off; there is no discharge path for the charge of capacitor Cgi, and the voltage across the capacitor is still +V m Si-3 is continuously on.

[0129] In the second signal dead time, switches Si-1 and Si-2 are off; there is no discharge path for the charge of capacitor Cgi, and the voltage across the capacitor is still -V m Si-3 is continuously off.

[0130] Embodiment 10:

[0131] A high-voltage switch assembly based on SiC MOSFET series, the main content is seen in embodiment 3, wherein the magnetic isolation driving module further comprises a voltage equalization circuit module.

[0132] The voltage equalization circuit module comprises voltage equalization resistors Rs and capacitors Cs connected in parallel at the drain and source terminals of the switch, respectively.

[0133] Embodiment 11:

[0134] A high-voltage switch assembly based on SiC MOSFET series, the main content is seen in embodiment 3, wherein the primary winding adopts a direct-current high-voltage insulated wire.

Claims

1. A high-voltage switch component based on SiC MOSFET series connection, characterized by: Includes magnetic isolation drive module; The magnetic isolation drive module includes n cascaded magnetic isolation drive circuits; the integer n is ≥ 1; Each magnetic isolation drive circuit includes at least a number of switch tubes, a number of resistors and a magnetic ring; Each magnetic ring is wound with a secondary winding; The n magnetic rings are all mounted on the same magnetic core; a primary winding is arranged inside the magnetic core, and the primary winding passes through both ends of the magnetic core; Among them, the circuit topology of the i-th magnetic isolation drive circuit is as follows: The two ends of the secondary winding wound on the i-th magnetic ring are Bi1 and Bi2 respectively; One end of the resistor Ri-1 is connected to the Bi1 terminal of the secondary winding, and the other end is connected to the gate of the switch tube Si-1. The source of the switch tube Si-1 is connected to the Bi2 terminal of the secondary winding, and the drain is connected to the drain of the switch tube S(i+1)-3 of the i+1th magnetic isolation drive module. The source of the switch Si-2 is connected to the Bi1 terminal of the secondary winding, and the drain is connected in series with the resistor Rgi and then to the gate of the switch Si-3; the drain of the switch Si-2 is connected in series with the capacitor Cgi and then to the drain of the switch S(i+1)-3; The drain of the switch tube Si-2 is connected in series with a resistor Rgi and a bidirectional voltage regulator diode Zi, and then connected to the drain of the switch tube S(i+1)-3; the gate of the switch tube Si-2 is connected in series with a resistor Ri-2, and then connected to the drain of the switch tube S(i+1)-3; The source of the switch tube Si-3 is connected in series with the resistor Rli and then connected to the drain of the switch tube S(i+1)-3; When the magnetic isolation drive module is working, the primary winding receives the external drive signal; The magnetic core and the magnetic ring generate a control signal under the action of an external driving signal, and transmit the control signal to the magnetic isolation driving module through the secondary winding; The magnetic isolation drive module isolates the control signals of different switches and, under the action of the control signals, enables the series switches to operate synchronously and output high-voltage pulses.

2. The SiC MOSFET series high-voltage switch assembly according to claim 1, characterized in that: The switch tube Si-1, the switch tube Si-2, and the switch tube Si-3 each include a MOS tube and a body diode connected in parallel with the MOS tube.

3. The SiC MOSFET series high-voltage switch assembly according to claim 1, characterized in that: The resistor Rli is used to implement overcurrent protection for the switch tube.

4. The SiC MOSFET series high-voltage switch assembly according to claim 1, characterized in that: The control signal includes a first control signal and a second control signal; When the secondary winding transmits the first control signal to the magnetic isolation driving module, the magnetic isolation driving module is in a charging state; When the secondary winding transmits the second control signal to the magnetic isolation driving module, the magnetic isolation driving module is in a discharging state.

5. The SiC MOSFET series high-voltage switch assembly according to claim 4, characterized in that: When the magnetic isolation drive module is in the charging state, the switch Si-1 is turned on, the current passes through the body diode of Si-2, and then a closed loop is formed. The capacitor Cgi starts to charge until the voltage across the capacitor Cgi reaches +V m , the gate-source voltage of switch Si-3 reaches +V m , switch Si-3 is turned on.

6. The SiC MOSFET series high-voltage switch assembly according to claim 4, characterized in that: When the magnetic isolation drive module is in the discharge state, switch Si-2 is turned on, and the current passes through the body diode of switch Si-1, thereby forming a closed loop; capacitor Cgi begins to discharge, and then capacitor Cgi begins to charge in the reverse direction until the voltage across capacitor Cgi reaches -V m , the drain-source voltage of switch Si-3 becomes -V m , switch Si-3 is turned off.

7. The SiC MOSFET series high-voltage switch assembly according to claim 4, characterized in that: The conversion time of the magnetic isolation drive module from the charging state to the discharging state is the first signal dead time, and the conversion time from the discharging state to the charging state is the second signal dead time; During the first signal dead zone, switches Si-1 and Si-2 are turned off; the charge of capacitor Cgi has no discharge path, and the voltage across both ends remains +V m , switch Si-3 is continuously turned on; During the second signal dead time, switches Si-1 and Si-2 are turned off; the charge of capacitor Cgi has no discharge path, and the voltage across both ends remains -V m , switch Si-3 is continuously turned off.

8. The SiC MOSFET series high-voltage switch assembly according to claim 1, characterized in that: The magnetic isolation driving module also includes a voltage equalization circuit module; The voltage balancing circuit module includes a voltage balancing resistor Rs and a capacitor Cs respectively connected in parallel to the drain and source ends of the switch.

9. The SiC MOSFET series high-voltage switch assembly according to claim 1, characterized in that: The primary winding adopts a DC high voltage insulated wire.

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