A driving power supply circuit for a silicon carbide switching tube
By designing a silicon carbide switch tube driving power supply circuit including half-bridge circuit, transformer, resonant inductor and resonant capacitor, the problems of narrow input voltage range and increased loss in traditional power supply circuits are solved, and a wide input voltage range, high conversion efficiency and stable output are achieved.
Patent Information
- Application Number
- CN202411925426.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2025-04-04
AI Technical Summary
The input voltage range of the drive power supply circuit of traditional silicon carbide switch tubes is narrow, and the loss increases with the increase in switching frequency, which seriously affects the system efficiency.
A silicon carbide switch tube driving power supply circuit including half-bridge circuit, transformer, resonant inductor and resonant capacitor is designed. Through PWM variable duty cycle control and low dropout linear regulator voltage division, a wide input voltage range and high conversion efficiency are achieved.
The wide input voltage range, low loss and high efficiency of the SiC switch tube driving power supply circuit is realized, reducing the volume of the power supply circuit and providing a stable positive and negative voltage output.
Smart Images
Figure CN119765936A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of driving a silicon carbide switch tube, and in particular to a driving power supply circuit of a silicon carbide switch tube. Background Art
[0002] Silicon carbide materials have the characteristics of large bandgap width, high critical breakdown electric field strength, and fast saturation drift speed. Therefore, the application of silicon carbide switch tubes can greatly increase the switching frequency and improve the power density of products. Silicon carbide gradually replaces silicon semiconductor devices and is widely used in high-voltage and high-frequency circuits.
[0003] The driving power circuit is the key link for the safe and reliable operation of silicon carbide switches. Traditional driving power circuits use LLC resonant circuits with variable frequency control or phase-shifted full-bridge circuits with PWM phase-shift control. These circuits have a narrow input voltage range. The loss of traditional driving power circuits increases in direct proportion to the increase in the switching frequency of their own switching devices. Especially when wide bandgap power devices are used in high-frequency and ultra-high-frequency systems, the increase in the loss of the driving power circuit seriously affects the system efficiency. Summary of the invention
[0004] In order to solve the above technical problem or at least partially solve the above technical problem, the present invention provides a driving power supply circuit for a silicon carbide switching tube.
[0005] The present invention provides a driving power supply circuit of a silicon carbide switch tube, comprising: a switch tube T 1 And switch tube T 2 The half-bridge circuit is formed, and the midpoint of the bridge arm of the half-bridge circuit is connected to the resonant inductor L r The first end is connected to the resonant inductor L r The second end is connected to the transformer T r The non-same-name ends of the primary side are connected; the resonant capacitor C r1 and resonant capacitor C r2 The first end of the switch tube T 1 The drain and switch tube T 2 The source of the resonant capacitor C r1 and resonant capacitor C r2 The second end is connected to the transformer T r The same-name terminal of the primary side; transformer T r The magnetizing inductance is L m ; Switching tube T 3 Connected to transformer T r The secondary side with the same name terminal and capacitor C o Between the negative terminals, capacitor C o The negative terminal is connected to the negative output terminal; transformer T r The secondary side non-identical terminal and capacitor C oThe positive end is connected to the input end of the low voltage drop linear regulator, the ground end of the low voltage drop linear regulator is connected to the negative output end, and the output end of the low voltage drop linear regulator is connected to the positive output end; the resistor R and the Zener diode Z are connected in series between the positive output end and the negative output end, and the capacitor C 1 and capacitor C 2 The driving power circuit of the silicon carbide switching tube is connected in parallel with the resistor R and the Zener diode Z respectively, and provides the required positive voltage V+ and negative voltage V- for driving the silicon carbide switching tube.
[0006] Furthermore, the switch tube T 1 And switch tube T 3 The driving signal is PWM1, the switch tube T 2 The driving signal is PWM2; wherein the driving signals PWM1 and PWM2 are both square waves with fixed frequencies, and the driving signals PWM1 and PWM2 are complementary signals.
[0007] Furthermore, the duty cycle of the driving signal PWM1 is:
[0008]
[0009] Among them, V g is the input voltage, n is the transformer T r The ratio of primary to secondary winding turns, V 0 is the capacitance C o Voltage.
[0010] Furthermore, the driving power circuit of the silicon carbide switch tube is in mode 1, the driving signal PWM1 changes from high level to low level, the driving signal PWM2 is low level, and the current flowing through the excitation inductor L m The excitation current i m and flows through the resonant inductor L r The resonant current i r Equal and in reverse state, the switch tube T 1 The output capacitor is charged, and the switch tube T 2 The output capacitor is discharged, and then the switch tube T 2 The body diode of the switch tube T is turned on, and the excess energy of the resonant cavity is transferred to the input end; 3 In the off state, the output is connected to the capacitor C o To provide energy, the output of the low-dropout linear regulator is divided by resistor R and Zener diode Z to provide stable positive and negative voltages.
[0011] Furthermore, the driving power circuit of the silicon carbide switch tube is in mode 2, the driving signal PWM1 is at a low level, the driving signal PWM2 changes from a low level to a high level, and the switch tube T 1 And switch tube T 3 In the off state, the switch tube T2 It is in the on state; the current flowing through the excitation inductance L m The excitation current i m and flows through the resonant inductor L r The resonant current i r The input voltage is equal and decreases in the reverse direction. After a period of time, it passes through zero and increases in the positive direction. The input voltage continues to be the resonant capacitor and transformer T r Charging and storing energy; switch tube T 3 In the off state, the output continues to be supplied by capacitor C o To provide energy, the output of the low-dropout linear regulator is divided by resistor R and Zener diode Z to provide stable positive and negative voltages.
[0012] Furthermore, the driving power circuit of the silicon carbide switch tube is in mode 3, the driving signal PWM1 is at a low level, and the driving signal PWM2 changes from a high level to a low level; the switch tube T 1 , switch tube T 2 And switch tube T 3 The tubes are all in the off state; the current flowing through the resonant inductor L r The resonant current i r In the forward state, the switch tube T 2 The output capacitor is charged, and the switch tube T 1 The output capacitor discharges, the switch tube T 1 The body diode is turned on; the resonant capacitor C r1 , resonant capacitor C r2 , resonant inductor L r With the excitation inductance L m In resonance state, and the resonance frequency is Excitation current i m With the resonant current i r Equal; switch tube T 3 In the off state, the output continues to be supplied by capacitor C o Provide energy, the output of the low-dropout linear regulator is divided by the resistor R and the Zener diode Z, and the output is stable positive and negative voltage, where C r is the resonant capacitor C r1 and resonant capacitor C r2 Capacitance value.
[0013] Furthermore, the driving signal PWM1 is at a high level, the driving signal PWM2 is at a low level, and the switch tube T 1 And switch tube T 3 In the on state, the switch tube T 2 It is in the off state; because the switch tube T 3 The tube is turned on, so the excitation inductance L m The voltage polarity is reversed, and the excitation current i m Starts to decrease positively, due to the excitation inductance Lm The voltage is clamped, so the resonant capacitor C r1 , resonant capacitor C r2 and resonant inductor L r In resonance state, and the resonance frequency is Excitation current i m With the resonant current i r will no longer be equal, the resonant capacitor and transformer transfer the stored energy to the output end, and after passing through the low voltage drop linear regulator, the voltage is divided by the resistor R and the Zener diode Z to output stable positive and negative voltages until the excitation current i m With the resonant current i r Again, C r is the resonant capacitor C r1 and resonant capacitor C r2 Capacitance value.
[0014] Furthermore, the driving power circuit of the silicon carbide switch tube is in mode 5, the driving signal PWM1 is high level, the driving signal PWM2 is low level, and the excitation current i m With the resonant current i r Equal again, at this time the switch tube T 1 In the on state, the switch tube T 2 It is in the off state; because the switch tube T 3 Turn off, resonant capacitor C r1 , resonant capacitor C r2 , resonant inductor L r With the excitation inductance L m It is in resonance again, and the resonant frequency is The output will continue to be connected to the capacitor C o Provide energy, after passing through the low voltage drop linear regulator, the voltage is divided by the resistor R and the Zener diode Z, and the output is a stable positive and negative voltage. r is the resonant capacitor C r1 and resonant capacitor C r2 Capacitance value.
[0015] Furthermore, the switch tube T 1 , switch tube T 2 And switch tube T 3 The switching frequency f s Must be greater than the resonant frequency f r1 and is less than the resonant frequency f r2 ,Right now:
[0016] f r1 <f s <f r2 ;
[0017]
[0018] Among them, C r is the resonant capacitor C r1 and resonant capacitor C r2 Capacitance value; L r is the resonant inductance, L m is the magnetizing inductance.
[0019] The above technical solution provided by the embodiment of the present invention has the following advantages compared with the prior art:
[0020] The purpose of the present invention is to provide a reliable and stable driving power supply circuit for a silicon carbide switch tube. The driving power supply circuit of the silicon carbide switch tube realizes the isolation function through a transformer and adopts PWM variable duty cycle control. Compared with the LLC resonant circuit variable frequency control and the phase-shifted full-bridge circuit PWM phase-shift control, the driving power supply circuit of the silicon carbide switch tube of the present invention has a wide input voltage range. At the same time, the transformer leakage inductance and the parasitic capacitance of the switch tube are used to participate in the resonance, so that the zero voltage turn-on of the primary switch tube and the zero current turn-off of the secondary switch tube within the full input voltage range are realized, thereby improving the conversion efficiency of the driving power supply circuit of the silicon carbide switch tube. The resonant capacitor is used to participate in energy storage, sharing the energy storage function of the transformer, and the volume of the resonant capacitor is negligible relative to the volume of the transformer. Therefore, relative to the traditional PWM variable duty cycle power supply, the volume of the driving power supply circuit of the silicon carbide switch tube is reduced. The present application has the characteristics of high efficiency, small volume, wide input voltage range, stable output positive and negative voltage, and simple structure. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.
[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.
[0023] Figure 1 A flow chart of a driving power circuit of a silicon carbide switch tube provided by an embodiment of the present invention;
[0024] Figure 2 A schematic diagram of the working timing and current waveform of the driving power circuit of the silicon carbide switch tube provided in an embodiment of the present invention;
[0025] Figure 3 A schematic diagram of an equivalent circuit of mode 1 of a driving power supply circuit of a silicon carbide switch tube provided in an embodiment of the present invention;
[0026] Figure 4 A schematic diagram of an equivalent circuit of mode 2 of a driving power supply circuit of a silicon carbide switch tube provided in an embodiment of the present invention;
[0027] Figure 5 A schematic diagram of an equivalent circuit of mode 3 of a driving power circuit of a silicon carbide switch tube provided in an embodiment of the present invention;
[0028] Figure 6 A schematic diagram of an equivalent circuit of mode 4 of a driving power circuit of a silicon carbide switch tube provided in an embodiment of the present invention;
[0029] Figure 7 A schematic diagram of an equivalent circuit of mode 5 of a driving power circuit of a silicon carbide switch tube provided in an embodiment of the present invention. DETAILED DESCRIPTION
[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0031] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.
[0032] Example 1
[0033] like Figure 1 As shown, the present invention implements a driving power circuit of a silicon carbide switch tube, including:
[0034] Switching tube T 1 And switch tube T 2 A half-bridge circuit is formed, and the midpoint of the bridge arm of the half-bridge circuit is connected to the resonant inductor L r The first end is connected to the resonant inductor L r The second end is connected to the transformer T r The non-same-named terminals of the primary side are connected. Resonant capacitor C r1 and resonant capacitor C r2 The first end of the switch tube T 1 The drain and switch tube T2 The source of the resonant capacitor C r1 and resonant capacitor C r2 The second end is connected to the transformer T r The same name terminal of the primary side. Transformer T r The magnetizing inductance is L m The primary-to-secondary winding turns ratio is defined as n:1. 3 Connected to transformer T r The secondary side with the same name terminal and capacitor C o Between the negative terminals, capacitor C o The negative terminal is connected to the negative output terminal, where the switch tube T 3 The drain of the transformer T r The secondary side has the same name, the switch tube T 3 The source and capacitor C o Negative terminal. Transformer T r The secondary side non-identical terminal and capacitor C o The positive end is connected to the input end of the low voltage drop linear regulator, the ground end GND of the low voltage drop linear regulator is connected to the negative output end, and the output end of the low voltage drop linear regulator is connected to the positive output end. Resistor R and Zener diode Z are connected in series between the positive output end and the negative output end, and capacitor C 1 and capacitor C 2 They are respectively connected in parallel with the resistor R and the Zener diode Z. The driving power supply circuit of the silicon carbide switch tube provides the positive voltage V+ and negative voltage V- required for driving the silicon carbide switch tube.
[0035] Switching tube T 1 And switch tube T 3 The driving signal is PWM1, the switch tube T 2 The driving signal PWM1 and PWM2 are both square waves with fixed frequencies, and PWM1 and PWM2 are complementary signals.
[0036] The duty cycle of the PWM1 signal is:
[0037]
[0038] Among them, V g is the input voltage, n is the transformer T r The ratio of primary to secondary winding turns, V 0 is the capacitance C o Voltage.
[0039] The following is based on Figure 2-7 To analyze the working state of the driving power circuit of the silicon carbide switching tube.
[0040] Mode 1: If Figure 2 and 3 As shown, at t 0-t 1 When the drive power circuit of the silicon carbide switch tube is in mode 1, the drive signal PWM1 changes from high level to low level, and the drive signal PWM2 is low level, which is in the dead time. At this time, the current flowing through the excitation inductor L m The excitation current i m and flows through the resonant inductor L r The resonant current i r Equal and in reverse state, the switch tube T 1 The output capacitor is charged, and the switch tube T 2 The output capacitor is discharged, and then the switch tube T 2 The body diode of the switch tube T is turned on, and the excess energy of the resonant cavity is transferred to the input end. 3 In the off state, the output is connected to the capacitor C o To provide energy, the output of the low-dropout linear regulator is divided by resistor R and Zener diode Z to provide stable positive and negative voltages.
[0041] Mode 2: If Figure 2 and 4 As shown, at t 1 -t 2 When the driving power circuit of the silicon carbide switch tube is in mode 2, the driving signal PWM1 is at a low level, and the driving signal PWM2 changes from a low level to a high level. At this time, the switch tube T 1 And switch tube T 3 In the off state, the switch tube T 2 is in the on state, because in mode 1 the switch tube T 2 The body diode of the switch tube T 2 In t 1 When the switch is turned on, it is turned on with zero voltage, realizing the switch tube T 2 Soft switch. The current flowing through the magnetizing inductor L m The excitation current i m and flows through the resonant inductor L r The resonant current i r The input voltage is equal and decreases in the reverse direction. After a period of time, it passes through zero and increases in the positive direction. The input voltage continues to be the resonant capacitor and transformer T r Charging and storing energy. Switching tube T 3 In the off state, the output continues to be supplied by capacitor C o To provide energy, the output of the low-dropout linear regulator is divided by resistor R and Zener diode Z to provide stable positive and negative voltages.
[0042] Mode 3: If Figure 2 and 5 As shown, at t 2 -t 3When the drive power circuit of the silicon carbide switch tube is in mode 3, the drive signal PWM1 is at a low level, the drive signal PWM2 is at a low level, and it is in the dead time. At this time, the switch tube T 1 , switch tube T 2 And switch tube T 3 The tubes are all in the off state. At this time, the current flowing through the resonant inductor L r The resonant current i r In the forward state, the switch tube T 2 The output capacitor is charged, and the switch tube T 1 The output capacitor discharges, the switch tube T 1 The body diode of the resonant capacitor C r1 , resonant capacitor C r2 , resonant inductor L r With the excitation inductance L m In resonance state, and the resonance frequency is Excitation current i m With the resonant current i r Equal. Switch tube T 3 In the off state, the output continues to be supplied by capacitor C o To provide energy, the output of the low-dropout linear regulator is divided by resistor R and Zener diode Z, and the output is stable positive and negative voltage.
[0043] Mode 4: If Figure 2 and 6 As shown, at t 3 -t 4 When the driving power circuit of the silicon carbide switch tube is in mode 4, the driving signal PWM1 is high level, and the driving signal PWM2 is low level. At this time, the switch tube T 1 And switch tube T 3 In the on state, the switch tube T 2 In mode 3, the switch tube T 1 The body diode of the switch tube T 1 In t 3 When the switch is turned on, it is turned on with zero voltage, realizing the switch tube T 1 Soft switch. 3 The tube is turned on, so the excitation inductance L m The voltage polarity is reversed, and the excitation current i m At the same time, due to the excitation inductance L m The voltage is clamped, so the resonant capacitor C r1 , resonant capacitor C r2 and resonant inductor L r In resonance state, and the resonance frequency is Excitation current i m With the resonant current i rThe resonant capacitor and transformer transfer the stored energy to the output end, and after passing through the low voltage drop linear regulator, the voltage is divided by the resistor R and the Zener diode Z to output stable positive and negative voltages. m With the resonant current i r Equal again, mode 4 ends.
[0044] Mode 5: If Figure 2 and 7 As shown, at t 4 -t 5 When the driving power circuit of the silicon carbide switch tube is in mode 5, the driving signal PWM1 is high level, and the driving signal PWM2 is low level. At this time, the switch tube T 1 In the on state, the switch tube T 2 In the off state, due to the excitation current i m With the resonant current i r Again, although the switch tube T 3 The tube drive signal PWM1 is high level but the switch tube T 3 There is no current flowing, so the switch tube T 3 When the tube is turned off, it is zero current turned off, realizing the switch tube T 3 Soft switch. 3 Turn off, resonant capacitor C r1 , C r2 , resonant inductor L r With the excitation inductance L m It is in resonance again, and the resonant frequency is The output will continue to be connected to the capacitor C o Provide energy, after passing through the low voltage drop linear regulator, the voltage is divided by resistor R and Zener diode Z to output stable positive and negative voltage.
[0045] To ensure the switch tube T 1 , switch tube T 2 And switch tube T 3 To achieve soft switching, the switch tube T 1 , switch tube T 2 And switch tube T 3 The switching frequency f s Must be greater than the resonant frequency f r1 and is less than the resonant frequency f r2 ,Right now:
[0046] f r1 <f s <f r2 .
[0047] In the embodiments provided by the present invention, it should be understood that the disclosed structure can be implemented in other ways. For example, the structural embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, structures or units, which can be electrical, mechanical or other forms.
[0048] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
[0049] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.
[0050] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.
Claims
1. A driving power supply circuit for a silicon carbide switch tube, characterized in that: include: The half-bridge circuit formed by the switch tube T1 and the switch tube T2 has a bridge arm midpoint and a resonant inductor L r The first end is connected to the resonant inductor L r The second end is connected to the transformer T r The non-same-name ends of the primary side are connected; the resonant capacitor C r1 and resonant capacitor C r2 The first end of the resonant capacitor C is connected to the drain of the switch tube T1 and the source of the switch tube T2. r1 and resonant capacitor C r2 The second end is connected to the transformer T r The same-name terminal of the primary side; transformer T r The magnetizing inductance is L m ; Switch tube T3 is connected to transformer T r The secondary side with the same name terminal and capacitor C o Between the negative terminals, capacitor C o The negative terminal is connected to the negative output terminal; transformer T r The secondary side non-identical terminal and capacitor C o The positive end is commonly connected to the input end of the low voltage difference linear regulator, the ground end of the low voltage difference linear regulator is connected to the negative output end, and the output end of the low voltage difference linear regulator is connected to the positive output end; the resistor R and the Zener diode Z are connected in series and connected between the positive output end and the negative output end, the capacitor C1 and the capacitor C2 are respectively connected in parallel with the resistor R and the Zener diode Z, and the driving power supply circuit of the silicon carbide switching tube provides the required positive voltage V+ and negative voltage V- for driving the silicon carbide switching tube.
2. The driving power supply circuit of the silicon carbide switch tube according to claim 1, characterized in that: The driving signals of the switch tubes T1 and T3 are PWM1, and the driving signal of the switch tube T2 is PWM2; wherein the driving signals PWM1 and PWM2 are both square waves with fixed frequencies, and the driving signals PWM1 and PWM2 are complementary signals.
3. The driving power supply circuit of the silicon carbide switch tube according to claim 2, characterized in that: The duty cycle of the driving signal PWM1 is: Among them, V g is the input voltage, n is the transformer T r The ratio of the number of turns of the primary and secondary windings, V0 is the capacitance C o Voltage.
4. The driving power supply circuit of the silicon carbide switch tube according to claim 2, characterized in that: The driving power circuit of the silicon carbide switch tube is in mode 1, the driving signal PWM1 changes from high level to low level, the driving signal PWM2 is low level, and the current flowing through the excitation inductor L m The excitation current i m and flows through the resonant inductor L r The resonant current i r The output capacitor of switch tube T1 is charged and the output capacitor of switch tube T2 is discharged. Then the body diode of switch tube T2 is turned on and the excess energy of the resonant cavity is transferred to the input end. Switch tube T3 is in the off state and the output end is connected to capacitor C o To provide energy, the output of the low-dropout linear regulator is divided by resistor R and Zener diode Z to provide stable positive and negative voltages.
5. The driving power supply circuit of the silicon carbide switch tube according to claim 2, characterized in that: The driving power circuit of the silicon carbide switch tube is in mode 2, the driving signal PWM1 is low level, the driving signal PWM2 changes from low level to high level, the switch tubes T1 and T3 are in the off state, and the switch tube T2 is in the on state; the current flowing through the excitation inductor L m The excitation current i m and flows through the resonant inductor L r The resonant current i r The input voltage is equal and decreases in the reverse direction. After a period of time, it passes through zero and increases in the positive direction. The input voltage continues to be the resonant capacitor and transformer T r Charging and storing energy; the switch tube T3 is in the off state, and the output end continues to be charged by the capacitor C o To provide energy, the output of the low-dropout linear regulator is divided by resistor R and Zener diode Z to provide stable positive and negative voltages.
6. The driving power supply circuit of the silicon carbide switch tube according to claim 2, characterized in that: The driving power circuit of the silicon carbide switch tube is in mode 3, the driving signal PWM1 is at a low level, and the driving signal PWM2 changes from a high level to a low level; the switch tubes T1, T2, and T3 are all in the off state; the current flowing through the resonant inductor L r The resonant current i r In the forward state, the output capacitor of switch tube T2 is charged, the output capacitor of switch tube T1 is discharged, and the body diode of switch tube T1 is turned on; the resonant capacitor C r1 , resonant capacitor C r2 , resonant inductor L r With the excitation inductance L m In resonance state, and the resonance frequency is Excitation current i m With the resonant current i r The switch tube T3 is in the off state, and the output end continues to be connected to the capacitor C o Provide energy, the output of the low-dropout linear regulator is divided by the resistor R and the Zener diode Z, and the output is stable positive and negative voltage, where C r is the resonant capacitor C r1 and resonant capacitor C r2 Capacitance value.
7. The driving power supply circuit of the silicon carbide switch tube according to claim 2, characterized in that: The drive signal PWM1 is high level, the drive signal PWM2 is low level, the switch tubes T1 and T3 are on, and the switch tube T2 is off; since the switch tube T3 is on, the excitation inductance L m The voltage polarity is reversed, and the excitation current i m Starts to decrease positively, due to the excitation inductance L m The voltage is clamped, so the resonant capacitor C r1 , resonant capacitor C r2 and resonant inductor L r In resonance state, and the resonance frequency is Excitation current i m With the resonant current i r will no longer be equal, the resonant capacitor and transformer transfer the stored energy to the output end, and after passing through the low voltage drop linear regulator, the voltage is divided by the resistor R and the Zener diode Z to output stable positive and negative voltages until the excitation current i m With the resonant current i r Again, C r is the resonant capacitor C r1 and resonant capacitor C r2 Capacitance value.
8. The driving power supply circuit of the silicon carbide switch tube according to claim 2, characterized in that: The driving power circuit of the silicon carbide switch tube is in mode 5, the driving signal PWM1 is high level, the driving signal PWM2 is low level, and the excitation current i m With the resonant current i r equal again, at this time, the switch tube T1 is in the on state, and the switch tube T2 is in the off state; because the switch tube T3 is turned off, the resonant capacitor C r1 , resonant capacitor C r2 , resonant inductor L r With the excitation inductance L m It is in resonance again, and the resonant frequency is The output will continue to be connected to the capacitor C o Provide energy, after passing through the low voltage drop linear regulator, the voltage is divided by the resistor R and the Zener diode Z, and the output is a stable positive and negative voltage. r is the resonant capacitor C r1 and resonant capacitor C r2 Capacitance value.
9. The driving power supply circuit of the silicon carbide switch tube according to claim 1, characterized in that: The switching frequency f of the switch tubes T1, T2 and T3 s Must be greater than the resonant frequency f r1 and is less than the resonant frequency f r2 ,Right now: f r1 <f s <f r2 ; Among them, C r is the resonant capacitor C r1 and resonant capacitor C r2 Capacitance value; L r is the resonant inductance, L m is the magnetizing inductance.