SiC MOSFET resonance drive circuit and control method
By introducing a resonant circuit into the SiC MOSFET drive circuit, circulating the energy of the input capacitor, solving the problem of high switching losses of SiC MOSFETs in high-frequency applications, achieving higher power density.
Patent Information
- Application Number
- CN202510266797.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-07
- Publication Date
- 2025-05-30
AI Technical Summary
In high-frequency applications, the switching loss of SiC MOSFETs is high, resulting in a reduced power density of the drive circuit.
The SiC MOSFET resonant driving circuit is adopted to resonate through the capacitor and inductor in the resonant circuit, and the energy stored in the input capacitor of the SiC MOSFET is recycled to reduce switching losses and driving power.
It effectively reduces the switching loss and required driving power of SiC MOSFET, and improves the power density of the driving system.
Smart Images
Figure CN120074191A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of power electronics technology, and in particular, to a SiC MOSFET resonant drive circuit and a control method thereof. Background Art
[0002] In recent years, due to the characteristics of high breakdown voltage, high thermal conductivity, and low on-resistance of SiC MOSFET devices, they have been widely used in fields such as motor control, wireless power transmission, and grid-connected inverters. SiC MOSFETs can operate at extremely high switching frequencies, and their operating frequencies can reach above MHz. The increase in switching frequency can reduce the size of passive devices such as capacitors and inductors, thereby reducing the device volume and increasing the power density. However, the drive loss of the device is proportional to the switching frequency. In high-frequency applications, the switching frequency and gate drive loss of SiC MOSFETs also increase proportionally, which requires a larger drive power module and reduces the power density of the SiC MOSFET drive system. Therefore, the design of the drive circuit is extremely important for SiC MOSFET devices, and it seriously affects the operating performance of the devices.
[0003] Currently, there are several main solutions to this problem. On the one hand, the main circuit of the SiC MOSFET application can be improved to enable the SiC MOSFET to achieve zero-voltage switching or zero-current switching, reducing the switching loss. However, this will increase the complexity of the main circuit design and is not applicable in some cases. On the other hand, an integrated resonant drive circuit can be used to recycle the energy in the input capacitance of the SiC MOSFET and reduce the drive loss. However, the design of the isolation transformer in the integrated resonant drive circuit is difficult and prone to saturation, which limits its application scenarios. Summary of the Invention
[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a SiC MOSFET resonant drive circuit and a control method thereof to solve the technical problem of high switching loss of SiC MOSFETs in high-frequency applications.
[0005] To achieve the above object, the present invention is implemented by the following technical solutions: In the first aspect, the present invention provides a SiC MOSFET resonant drive circuit, including: A half-bridge circuit, including a first switching tube and a second switching tube, the drain of the first switching tube is connected to the power supply V CC , the source of the first switching tube is connected to the drain of the second switching tube, and the source of the second switching tube is grounded; The resonant circuit includes a third switching transistor, a capacitor, and an inductor. The drain of the third switching transistor is connected to the source of the first switching transistor and one end of the inductor. The other end of the inductor is connected to the drain of the second switching transistor, one end of the capacitor, and the gate of the SiC MOSFET. The other end of the capacitor is connected to the source of the third switching transistor; A controller, whose output terminals are respectively connected to the gates of the first switching transistor, the second switching transistor, and the third switching transistor.
[0006] Optionally, the first switching transistor, the second switching transistor, and the third switching transistor are N-MOSFETs.
[0007] Optionally, an input capacitor C is connected between the gate and the source of the SiC MOSFET iss , and the source of the SiC MOSFET is grounded.
[0008] Optionally, the controller controls the conduction and cutoff of the first switching transistor, the second switching transistor, and the third switching transistor, so that the capacitor and the inductor in the resonant circuit resonate, and the input capacitor C of the SiC MOSFET iss is charged and discharged, and the SiC MOSFET is turned on and off.
[0009] In a second aspect, the present invention provides a control method for a SiC MOSFET resonant drive circuit. Based on the above resonant drive circuit, the control method includes: Step S11: Control the first switching transistor and the third switching transistor to conduct, and the second switching transistor to cutoff; Step S12: Control the first switching transistor to conduct, and the second switching transistor and the third switching transistor to cutoff; Step S13: Control the second switching transistor to conduct, and the first switching transistor and the third switching transistor to cutoff; Step S14: Control the first switching transistor, the second switching transistor, and the third switching transistor to cutoff; Wherein, the SiC MOSFET is turned on in step S12 and step S13, and the SiC MOSFET is turned off in step S11 and step S14.
[0010] Optionally, the resonant drive circuit has a total of 6 switching modes in one cycle, including: Mode 11: The first switching transistor and the third switching transistor conduct, the second switching transistor cutoff, and the power supply V CC charges the inductor, and the inductor current gradually rises; Mode 12: The third switching transistor cutoff, and the inductor current passes through the input capacitor C of the SiC MOSFET issThe freewheeling current is charged, and at this time, the gate current of the SiC MOSFET is approximately constant at the maximum value of the inductor current. The gate-source voltage of the SiC MOSFET gradually rises and conducts. Affected by the charging of the input capacitor C iss the third switch is approximately turned off at zero voltage; Mode 13: The input capacitor C of the SiC MOSFET iss is fully charged. The inductor current freewheels through the capacitor and the body diode of the second switch and gradually decreases; Mode 14: The second switch conducts. Since the inductor current drops to 0, the second switch is turned on at zero voltage, and the energy stored in the capacitor discharges through the inductor and the second switch; Mode 15: The second switch is turned off. The energy in the input capacitor C of the SiC MOSFET iss discharges through the inductor and the body diode of the first switch. At this time, the gate current of the SiC MOSFET is approximately constant at the minimum value of the inductor current. The gate-source voltage of the SiC MOSFET gradually decreases and turns off. Affected by the discharge of the input capacitor C iss the third switch is approximately turned off at zero voltage; Mode 16: The energy in the input capacitor C of the SiC MOSFET iss is completely discharged, and the inductor current freewheels through the body diodes of the first switch and the third switch.
[0011] In a third aspect, the present invention provides a control method for a resonant drive circuit of a SiC MOSFET. Based on the above SiC MOSFET resonant drive circuit, the control method includes: Step S21: Control the first switch and the third switch to conduct, and the second switch to turn off; Step S22: Control the first switch to conduct, and the second switch and the third switch to turn off; Step S23: Control the first switch and the second switch to conduct, and the third switch to turn off; Step S24: Control the second switch to conduct, and the first switch and the third switch to turn off; Step S25: Control the first switch, the second switch, and the third switch to turn off; wherein, the SiC MOSFET conducts in step S22, step S23, and step S24, and the SiC MOSFET turns off in step S21 and step S25.
[0012] Optionally, the resonant drive circuit has a total of 9 switching modes in one cycle, including: Mode 21: The first switch and the third switch conduct, the second switch turns off, and the power supply V CCCharge the inductor, and the inductor current gradually increases; Mode 22: Turn off the third switch tube, and the inductor current passes through the input capacitor C of the SiC MOSFET iss for freewheeling and charging it. At this time, the gate current of the SiC MOSFET is approximately constant at the maximum value of the inductor current, and the gate-source voltage of the SiC MOSFET gradually rises and conducts. Affected by the input capacitor C iss charging, the third switch tube approximately achieves zero-voltage turn-off; Mode 23: The input capacitor C of the SiC MOSFET iss charging is completed, the inductor current passes through the capacitor and the body diode of the second switch tube for freewheeling, and gradually decreases; Mode 24: Turn on the second switch tube M2. Since the inductor current passes through the capacitor and the body diode of the second switch tube for freewheeling, the second switch tube achieves zero-voltage turn-on; Mode 25: The energy stored in the capacitor is discharged through the inductor and the second switch tube; Mode 26: Turn off the first switch tube. Affected by the capacitor, there is no current flowing through the first switch tube at this time, and the first switch tube achieves zero-current turn-off; Mode 27: Turn off the second switch tube. The energy in the input capacitor C of the SiC MOSFET iss is discharged through the inductor and the body diode of the first switch tube. At this time, the gate current of the SiC MOSFET is approximately constant at the minimum value of the inductor current, and the gate-source voltage of the SiC MOSFET gradually decreases and turns off. Affected by the input capacitor C iss discharging, the second switch tube approximately achieves zero-voltage turn-off; Mode 28: The energy in the input capacitor C of the SiC MOSFET iss is completely discharged, and the inductor current passes through the body diodes of the first switch tube and the third switch tube for freewheeling; Mode 29: Turn on the first switch tube and the third switch tube. Since the inductor current passes through the body diodes of the first switch tube and the third switch tube for freewheeling, the first switch tube and the third switch tube achieve zero-voltage turn-on, and the inductor current gradually decreases to zero.
[0013] Compared with the prior art, the beneficial effects achieved by the present invention: The present invention provides a SiC MOSFET resonant drive circuit and a control method. By the resonance of the capacitor and inductor in the resonant circuit, the energy stored in the input capacitor C of the SiC MOSFET is recycled, reducing the switching loss and the required drive power. Compared with the traditional drive circuit, it can be achieved only by adding a modular resonant circuit, and the circuit is simple and easy to implement. iss Brief Description of the Drawings
[0014] Figure 1 It is the circuit schematic diagram of the SiC MOSFET resonant drive circuit provided in the first embodiment of the present invention; Figure 2 It is the timing diagram of the control method provided in the second embodiment of the present invention; Figure 3 It is the timing diagram of the control method provided in the third embodiment of the present invention; Figure 4 It is the working schematic diagram of the resonant drive circuit in Mode 11 provided by the embodiment of the present invention; Figure 5 It is the working schematic diagram of the resonant drive circuit in Mode 12 provided by the embodiment of the present invention; Figure 6 It is the working schematic diagram of the resonant drive circuit in Mode 13 provided by the embodiment of the present invention; Figure 7 It is the working schematic diagram of the resonant drive circuit in Mode 14 provided by the embodiment of the present invention; Figure 8 It is the working schematic diagram of the resonant drive circuit in Mode 15 provided by the embodiment of the present invention; Figure 9 It is the working schematic diagram of the resonant drive circuit in Mode 16 provided by the embodiment of the present invention. Detailed implementation manners
[0015] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and cannot be used to limit the protection scope of the present invention.
[0016] Embodiment 1: As Figure 1 shown, the embodiment of the present invention provides a SiC MOSFET resonant drive circuit, including a half-bridge circuit, a resonant circuit, and a controller. The half-bridge circuit includes a first switching transistor M 1 and a second switching transistor M 2 . The drain of the first switching transistor M 1 is connected to the power supply V CC . The source of the first switching transistor M 1 is connected to the drain of the second switching transistor M 2 . The source of the second switching transistor M 2 is grounded. The resonant circuit includes a third switching transistor M 3 , a capacitor C, and an inductor L. The drain of the third switching transistor M 3 is connected to the source of the first switching transistor M 1 and one end of the inductor L. The other end of the inductor L is connected to the drain of the second switching transistor M 2 , one end of the capacitor C, and the gate of the SiC MOSFET. The other end of the capacitor C is connected to the third switching transistor M 3the source electrode. The output terminals of the controller are respectively connected to the first switching transistor M 1 , the second switching transistor M 2 and the third switching transistor M 3 at their gate electrodes. The drive signals of the first switching transistor M 1 , the second switching transistor M 2 and the third switching transistor M 3 are issued by the controller. The conduction and cutoff of the SiC MOSFET change with the change of the drive signals output by the controller.
[0017] An input capacitor C iss is connected between the gate and source electrodes of the SiC MOSFET, and the source electrode of the SiC MOSFET is grounded. The controller controls the conduction and cutoff of the first switching transistor M 1 , the second switching transistor M 2 and the third switching transistor M 3 to cause the capacitor C and the inductor L in the resonant circuit to resonate, so that the input capacitor C iss of the SiC MOSFET is charged and discharged, causing the SiC MOSFET to conduct and cutoff, and the energy in the input capacitor C iss is recycled, reducing the switching loss.
[0018] Specifically, in this embodiment, the first switching transistor M 1 , the second switching transistor M 2 and the third switching transistor M 3 are N-MOSFETs. Compared with transistors, field effect transistors have lower power consumption and faster switching speed, and are more suitable for the SiC MOSFET resonant drive circuit of this embodiment, thus realizing low-loss switching.
[0019] Embodiment 2:
[0020] Based on the above resonant drive circuit, an embodiment of the present invention provides a control method for a SiC MOSFET resonant drive circuit, including: Step S11: Control the first switching transistor M 1 and the third switching transistor M 3 to conduct, and the second switching transistor M 2 to cutoff; Step S12: Control the first switching transistor M 1 to conduct, and the second switching transistor M 2 and the third switching transistor M 3 to cutoff; Step S13: Control the second switching transistor M 2 to conduct, and the first switching transistor M 1 and the third switching transistor M 3 to cutoff; Step S14: Control the first switching transistor M 1 , the second switching transistor M 2 , and the third switching transistor M 3 to turn off; Among them, the SiC MOSFET is turned on in steps S12 and S13, and the SiC MOSFET is turned off in steps S11 and S14.
[0021] As Figure 2 shown, it is the timing diagram of the control method of the SiC MOSFET resonant drive circuit. In the steady state, there are a total of 6 switching modes in one cycle of the resonant drive circuit, which respectively correspond to Figure 2 in [t 0 -t 1 , [t 1 -t 2 , [t 2 -t 3 , [t 3 -t 4 , [t 4 -t 5 , and [t 5 -t 6 . The working principles of each mode are analyzed specifically below. To simplify the analysis process, it is assumed that all components in the circuit are ideal components.
[0022] Mode 11 [t 0 -t 1 : As Figure 4 shown, the first switching transistor M 1 and the third switching transistor M 3 are turned on, the second switching transistor M 2 is turned off, the power supply V CC charges the inductor L, and the inductor current i L gradually increases.
[0023] Mode 12 [t 1 -t 2 : As Figure 5 shown, the third switching transistor M 3 is turned off, the current in the inductor L continues to flow through the input capacitance C iss of the SiC MOSFET and charges it. At this time, the gate current of the SiC MOSFET is approximately constant at the maximum value i max of the inductor current. The gate-source voltage of the SiC MOSFET gradually rises and turns on. Affected by the charging of the input capacitance C iss , the third switching transistor M 3 is approximately turned off with zero voltage.
[0024] Mode 13 [t 2 -t 3:As shown in Figure 6 , the input capacitance C of the SiC MOSFET iss is charged. The current in the inductor L continues to flow through the capacitance C and the body diode of the second switching transistor M 2 and gradually decreases.
[0025] Mode 14 [t 3 -t 4 :As shown in Figure 7 , at time t 3 , the second switching transistor M 2 turns on. Since the current in the inductor L decreases to 0, the second switching transistor M 2 achieves zero-voltage turn-on. The energy stored in the capacitance C discharges through the inductor L and the second switching transistor M 2 , and the current in the inductor L is in the opposite direction to that shown in the figure.
[0026] Mode 15 [t 4 -t 5 :As shown in Figure 8 , the second switching transistor M 2 turns off. The energy in the input capacitance C of the SiC MOSFET iss discharges through the inductor L and the body diode of the first switching transistor M 1 . The current in the inductor L is in the opposite direction to that shown in the figure. At this time, the gate current of the SiC MOSFET is approximately constant at the minimum value i min of the inductor current. The gate-source voltage of the SiC MOSFET gradually decreases and turns off. Affected by the discharge of the input capacitance C iss , the third switching transistor M 3 approximately achieves zero-voltage turn-off.
[0027] Mode 16 [t 5 -t 6 :As shown in Figure 9 , after the energy in the input capacitance C of the SiC MOSFET iss is discharged, the current in the inductor L continues to flow through the body diodes of the first switching transistor M 1 and the third switching transistor M 3 .
[0028] After time t 6 , the working state of the resonant drive circuit returns to Mode 11 and will not be repeated.
[0029] Analyze the losses of the proposed resonant drive circuit for the SiC MOSFET. Since Figure 2 shown in t 1 -t 2 and t 4 -t 5The duration is short, and its loss is ignored. The durations of the remaining four time periods are respectively: ; ; ; ;
[0030] where t 0-1 represents Figure 2 the duration from the moment t 0 to the moment t 1 , t 1-3 represents Figure 2 the duration from the moment t 1 to the moment t 3 , t 3-4 represents Figure 2 the duration from the moment t 3 to the moment t 4 , t 4-6 represents Figure 2 the duration from the moment t 4 to the moment t 6 . D represents the duty cycle of the SiC MOSFET, T represents the switching period of the SiC MOSFET, i min represents the minimum value of the inductor L current, and i max represents the maximum value of the inductor L current.
[0031] The effective values of the currents flowing through the first switch tube M 1 , the second switch tube M 2 and the third switch tube M 3 are respectively: ; ; ;
[0032] The effective values of the currents flowing through the freewheeling diodes of the first switch tube M 1 , the second switch tube M 2 and the third switch tube M 3 are respectively: ; ; ;
[0033] Then the losses caused by the first switch tube M 1 , the second switch tube M 2 and the third switch tube M 3 are:
[0034] In the formula, R M1 represents the on-resistance of the first switching transistor M 1 , R M2 represents the on-resistance of the second switching transistor M 2 , R M3 represents the on-resistance of the third switching transistor M 3 , R D1 represents the on-resistance of the body diode of the first switching transistor M 1 , R D2 represents the on-resistance of the body diode of the second switching transistor M 2 , R D3 represents the on-resistance of the body diode of the third switching transistor M 3 .
[0035] Analyze the losses of the proposed SiC MOSFET resonant drive circuit, so as to verify the technical effects of the control method of the SiC MOSFET resonant drive circuit proposed in this embodiment.
[0036] Embodiment 3: Based on the above SiC MOSFET resonant drive circuit, an embodiment of the present invention provides a control method for a SiC MOSFET resonant drive circuit, and the control method includes: Step S21: Control the first switching transistor and the third switching transistor to conduct, and the second switching transistor to turn off; Step S22: Control the first switching transistor to conduct, and the second switching transistor and the third switching transistor to turn off; Step S23: Control the first switching transistor and the second switching transistor to conduct, and the third switching transistor to turn off; Step S24: Control the second switching transistor to conduct, and the first switching transistor and the third switching transistor to turn off; Step S25: Control the first switching transistor, the second switching transistor and the third switching transistor to turn off; Wherein, the SiC MOSFET conducts in step S22, step S23 and step S24, and the SiC MOSFET turns off in step S21 and step S25.
[0037] As Figure 3 shown, it is a timing diagram of the control method of the SiC MOSFET resonant drive circuit. Compared with Embodiment 2, this method is easier to implement. Under steady state, there are a total of 9 switching modes in one cycle of the resonant drive circuit, which respectively correspond to Figure 3 in [t 0 -t 1 , [t 1 -t 2 , [t 2 -t3 , [t 3 -t 4 , [t 4 -t 5 , [t 5 -t 6 , [t 6 -t 7 , [t 7 -t 8 and [t 8 -t 9 , the working principles of each mode are analyzed as follows. To simplify the analysis process, it is assumed that all components in the circuit are ideal components.
[0038] Mode 21 [t 0 -t 1 : As Figure 4 shown, the first switch tube M 1 and the third switch tube M 3 are turned on, the second switch tube M 2 is turned off, and the power supply V CC charges the inductor L, and the inductor current i L gradually rises.
[0039] Mode 22 [t 1 -t 2 : As Figure 5 shown, the third switch tube M 3 is turned off, and the current in the inductor L flows through the input capacitor C iss of the SiC MOSFET to freewheel and charge it. At this time, the gate current of the SiC MOSFET is approximately constant at the maximum value of the inductor current i max , and the gate-source voltage of the SiC MOSFET gradually rises and turns on. Affected by the charging of the input capacitor C iss , the third switch tube M 3 is approximately turned off at zero voltage.
[0040] Mode 23 [t 2 -t 3 : As Figure 6 shown, the charging of the input capacitor C iss of the SiC MOSFET is completed, and the current in the inductor L flows through the capacitor C and the body diode of the second switch tube M 2 to freewheel and gradually decreases.
[0041] Mode 24 [t 3 -t 4 : As Figure 6 shown, at time t 3 the second switch tube M 2 is turned on. Since the current in the inductor L flows through the capacitor C and the second switch tube M2 The body diode of the second switch tube M 2 realizes zero-voltage turn-on.
[0042] Mode 25[t 4 -t 5 : As Figure 7 shown, the energy stored in the capacitor C discharges through the inductor L and the second switch tube M 2 , and the current of the inductor L is in the opposite direction to the direction shown in the figure.
[0043] Mode 26[t 5 -t 6 : As Figure 7 shown, at time t 5 , the first switch tube M 1 turns off. Affected by the capacitor C, there is no current flowing through the first switch tube M 1 , and it realizes zero-current turn-off.
[0044] Mode 27[t 6 -t 7 : As Figure 8 shown, the second switch tube M 2 turns off. The energy in the input capacitor C of the SiC MOSFET discharges through the inductor L and the body diode of the first switch tube M iss . The current of the inductor L is in the opposite direction to the direction shown in the figure. At this time, the gate current of the SiC MOSFET is approximately constant at the minimum value i 1 of the inductor current. The gate-source voltage of the SiC MOSFET gradually decreases and turns off. Affected by the discharge of the input capacitor C min , the second switch tube M iss approximately realizes zero-voltage turn-off. 2
[0045] Mode 28[t 7 -t 8 : As Figure 9 shown, the energy discharge in the input capacitor C of the SiC MOSFET is completed. The current in the inductor L continues to flow through the body diodes of the first switch tube M iss and the third switch tube M 1 . 3
[0046] Mode 29[t 8 -t 9 : As Figure 9 shown, the first switch tube M 1 and the third switch tube M 3 turn on. Since the current in the inductor L continues to flow through the body diodes of the first switch tube M 1 and the third switch tube M 3 , the first switch tube M1 and the third switching transistor M 3 achieve zero-voltage turn-on, and the inductor current gradually decreases to zero.
[0047] After the moment t8, the working state of the resonant drive circuit returns to Mode 21, which will not be repeated here.
[0048] Similar to Embodiment 2, the losses of the proposed resonant drive circuit under the control method of this embodiment can be calculated, so as to verify the technical effect of the control method of the SiC MOSFET resonant drive circuit proposed in this embodiment.
[0049] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.
Claims
1. A SiC MOSFET resonant drive circuit, characterized in that: include: The half-bridge circuit includes a first switch tube and a second switch tube, wherein the drain of the first switch tube is connected to a power supply V CC , the source of the first switch tube is connected to the drain of the second switch tube, and the source of the second switch tube is grounded; A resonant circuit, comprising a third switch tube, a capacitor and an inductor, wherein the drain of the third switch tube is connected to the source of the first switch tube and one end of the inductor, the other end of the inductor is connected to the drain of the second switch tube, one end of the capacitor and the gate of the SiC MOSFET, and the other end of the capacitor is connected to the source of the third switch tube; A controller, wherein an output end thereof is respectively connected to the gates of the first switch tube, the second switch tube and the third switch tube.
2. The SiC MOSFET resonant drive circuit according to claim 1, characterized in that: The first switch tube, the second switch tube and the third switch tube are N-MOSFETs.
3. The SiC MOSFET resonant drive circuit according to claim 1, characterized in that: An input capacitor C is connected between the gate and source of the SiC MOSFET. iss , the source of the SiC MOSFET is grounded.
4. The SiC MOSFET resonant drive circuit according to claim 3, characterized in that: The controller controls the on and off of the first switch tube, the second switch tube, and the third switch tube to cause the capacitor and the inductor in the resonant circuit to resonate, so that the input capacitor C iss Charging and discharging turn the SiC MOSFET on and off.
5. A control method for a SiC MOSFET resonant drive circuit, characterized in that: Based on the resonant drive circuit according to any one of claims 1 to 4, the control method comprises: Step S11: controlling the first switch tube and the third switch tube to be turned on, and the second switch tube to be turned off; Step S12: Control the first switch tube to be turned on, and the second switch tube and the third switch tube to be turned off; Step S13: Control the second switch tube to be turned on, and the first switch tube and the third switch tube to be turned off; Step S14: Control the first switch tube, the second switch tube, and the third switch tube to be turned off; The SiC MOSFET is turned on in step S12 and step S13 , and the SiC MOSFET is turned off in step S11 and step S14 .
6. The control method of the SiC MOSFET resonant drive circuit according to claim 5, characterized in that: The resonant drive circuit has a total of 6 switching modes in one cycle, including: Mode 11: The first switch tube and the third switch tube are turned on, the second switch tube is turned off, and the power supply V CC The inductor is charged and the inductor current gradually increases; Mode 12: The third switch is turned off, and the inductor current flows through the input capacitor C of the SiC MOSFET. iss The gate current of the SiC MOSFET is approximately constant at the maximum value of the inductor current. The gate-source voltage of the SiC MOSFET gradually rises and turns on, affected by the input capacitor C. iss Due to the influence of charging, the third switch tube can be turned off at approximately zero voltage. Mode 13: Input capacitance C of SiC MOSFET iss After charging is completed, the inductor current flows through the capacitor and the body diode of the second switch tube and gradually decreases; Mode 14: The second switch is turned on. As the inductor current drops to 0, the second switch is turned on at zero voltage, and the energy stored in the capacitor is discharged through the inductor and the second switch. Mode 15: The second switch is turned off, and the input capacitance C of the SiC MOSFET iss The energy is discharged through the inductor and the body diode of the first switch tube. At this time, the gate current of the SiC MOSFET is approximately constant at the minimum value of the inductor current. The gate-source voltage of the SiC MOSFET gradually decreases and turns off, affected by the input capacitor C. iss Due to the influence of discharge, the third switch tube is approximately turned off at zero voltage; Mode 16: Input capacitance C of SiC MOSFET iss After the energy is discharged, the inductor current continues to flow through the body diodes of the first switch tube and the third switch tube.
7. A control method for a SiC MOSFET resonant drive circuit, characterized in that: Based on the SiC MOSFET resonant drive circuit according to any one of claims 1 to 4, the control method includes: Step S21: Control the first switch tube and the third switch tube to be turned on, and the second switch tube to be turned off; Step S22: Control the first switch tube to be turned on, and the second switch tube and the third switch tube to be turned off; Step S23: controlling the first switch tube and the second switch tube to be turned on, and the third switch tube to be turned off; Step S24: controlling the second switch tube to be turned on, and the first switch tube and the third switch tube to be turned off; Step S25: Control the first switch tube, the second switch tube and the third switch tube to be turned off; The SiC MOSFET is turned on in step S22 , step S23 , and step S24 , and the SiC MOSFET is turned off in step S21 and step S25 .
8. The control method of the SiC MOSFET resonant drive circuit according to claim 7, characterized in that: The resonant drive circuit has a total of 9 switching modes in one cycle, including: Mode 21: The first switch tube and the third switch tube are turned on, the second switch tube is turned off, and the power supply V CC The inductor is charged and the inductor current gradually increases; Mode 22: The third switch is turned off, and the inductor current flows through the input capacitor C of the SiC MOSFET. iss The gate current of the SiC MOSFET is approximately constant at the maximum value of the inductor current. The gate-source voltage of the SiC MOSFET gradually rises and turns on, affected by the input capacitor C. iss Due to the influence of charging, the third switch tube can be turned off at approximately zero voltage. Mode 23: Input capacitance C of SiC MOSFET iss After charging is completed, the inductor current flows through the capacitor and the body diode of the second switch tube and gradually decreases; Mode 24: The second switch tube M2 is turned on. Since the inductor current flows through the capacitor and the body diode of the second switch tube, the second switch tube is turned on at zero voltage. Mode 25: The energy stored in the capacitor is discharged through the inductor and the second switch tube; Mode 26: The first switch tube is turned off. Affected by the capacitor, no current flows through the first switch tube at this time, and the first switch tube is turned off at zero current. Mode 27: The second switch is turned off, and the input capacitance C of the SiC MOSFET iss The energy is discharged through the inductor and the body diode of the first switch tube. At this time, the gate current of the SiC MOSFET is approximately constant at the minimum value of the inductor current. The gate-source voltage of the SiC MOSFET gradually decreases and turns off, affected by the input capacitor C. iss Due to the influence of discharge, the second switch tube is approximately turned off at zero voltage; Mode 28: Input capacitance C of SiC MOSFET iss After the energy is discharged, the inductor current continues to flow through the body diodes of the first switch tube and the third switch tube; Mode 29: The first switch tube and the third switch tube are turned on. Since the inductor current continues to flow through the body diodes of the first switch tube and the third switch tube, the first switch tube and the third switch tube are turned on at zero voltage, and the inductor current gradually decreases to zero.