阅读说明：本技术 一种隔离50kV高压的SiC MOSFET驱动电路 (SiC MOSFET drive circuit for isolating 50kV high voltage ) 是由 张宏韬 冯春红 胡玲 陈伟吉 于 2021-07-16 设计创作，主要内容包括：本发明的一个实施例公开了一种隔离50kV高压的SiC MOSFET驱动电路,包括：脉冲前后沿产生电路、驱动放大电路、高压驱动脉冲变压器、高压侧驱动控制电路以及SiC MOSFET；驱动电路工作时,调制脉冲经过脉冲前后沿产生电路产生导通窄脉冲串和截止窄脉冲串,经驱动放大电路放大和高压驱动脉冲变压器传输后,给SiC MOSFET的GS间结电容充电,产生与调制脉冲等宽的SiC MOSFET驱动电压。本发明不仅能够给浮动在50kV高压上的SiCMOSFET提供正常驱动电压,一致性好,还能兼顾宽脉冲和窄脉冲,适合复杂调制脉冲波形,同时没有高压隔离供电电路,电路简单。(One embodiment of the invention discloses a SiC MOSFET drive circuit for isolating 50kV high voltage, which comprises: the device comprises a pulse front-back edge generating circuit, a driving amplifying circuit, a high-voltage driving pulse transformer, a high-voltage side driving control circuit and a SiC MOSFET; when the driving circuit works, modulation pulses generate a conducting narrow pulse string and a stopping narrow pulse string through the pulse front and back edge generating circuit, and after the modulation pulses are amplified by the driving amplifying circuit and transmitted by the high-voltage driving pulse transformer, the modulation pulses charge the GS internode capacitance of the SiC MOSFET to generate SiC MOSFET driving voltage with the same width as the modulation pulses. The invention can not only provide normal driving voltage for the SiCMOS MOSFET floating on 50kV high voltage, has good consistency, but also can give consideration to wide pulse and narrow pulse, is suitable for complex modulation pulse waveform, does not have a high-voltage isolation power supply circuit, and has simple circuit.)

1. A SiC MOSFET drive circuit that isolates a 50kV high voltage, comprising:

the device comprises a pulse front-back edge generating circuit, a driving amplifying circuit, a high-voltage driving pulse transformer, a high-voltage side driving control circuit and a SiC MOSFET;

the pulse front and rear edge generating circuit is used for receiving external direct-current voltage and modulation pulse, generating a conduction narrow pulse string and a cut-off narrow pulse string, and sending the conduction narrow pulse string and the cut-off narrow pulse string to the driving amplifying circuit;

the drive amplifying circuit is used for receiving the conducting narrow pulse string and the stopping narrow pulse string, generating a positive conducting narrow pulse string and a negative stopping narrow pulse string and sending the positive conducting narrow pulse string and the negative stopping narrow pulse string to the high-voltage drive pulse transformer;

when the modulation pulse is at a high level, the high-voltage driving pulse transformer is used for sending the received forward conduction narrow pulse train to the high-voltage side driving control circuit;

when the modulation pulse is at a low level, the high-voltage driving pulse transformer is used for sending the received negative cut-off narrow pulse train to the high-voltage side driving control circuit;

the high-voltage side drive control circuit is used for converting the received positive-direction conduction narrow pulse string into a drive positive voltage of the SiC MOSFET and converting the received negative-direction cut-off narrow pulse string into a drive negative voltage of the SiC MOSFET, so that a SiC MOSFET drive voltage with the same width as the modulation pulse is generated.

2. The circuit of claim 1,

the duration of the conduction narrow pulse train is the same as the high level time of the modulation pulse;

the duration of the cut-off narrow pulse train is the same as the modulation pulse low level time.

3. The circuit of claim 1,

the output end of the pulse front and back edge generating circuit is connected with the input end of the driving amplifying circuit;

the output end of the drive amplifying circuit is connected with the first end of the high-voltage drive pulse transformer;

the second end of the high-voltage driving pulse transformer is connected with the first end of the high-voltage side driving control circuit, and the third end of the high-voltage driving pulse transformer is connected with the second end of the high-voltage side driving control circuit;

the third end of the high-voltage side drive control circuit is connected with the first end of the SiC MOSFET;

and the fourth end of the high-voltage side drive control circuit is connected with the second end of the SiC MOSFET.

4. The circuit of claim 3,

the high-voltage side drive control circuit includes: the driving circuit comprises a matching resistor, an 18V voltage stabilizing diode, a 3.9V voltage stabilizing diode, a 1.8V voltage stabilizing diode, a 5.1V voltage stabilizing diode, a conducting driving MOSFET, a cut-off driving MOSFET and a driving resistor;

the first end of the matching resistor is connected with the second end of the high-voltage driving pulse transformer and the cathode of the 18V voltage stabilizing diode;

the second end of the matching resistor is connected with the third end of the high-voltage driving pulse transformer and the cathode of the 3.9V voltage stabilizing diode;

the anode of the 18V voltage stabilizing diode is connected with the anode of the 3.9V voltage stabilizing diode;

the first end of the conduction driving MOSFET is connected with the cathode of the 18V voltage stabilizing diode, the second end of the conduction driving MOSFET is connected with the anode of the 1.8V voltage stabilizing diode, and the third end of the conduction driving MOSFET is connected with the cathode of the 5.1V voltage stabilizing diode and the first end of the driving resistor;

the first end of the cut-off driving MOSFET is connected with the cathode of the 3.9V voltage stabilizing diode and the cathode of the 1.8V voltage stabilizing diode, and the second end of the cut-off driving MOSFET is connected with the anode of the 5.1V voltage stabilizing diode.

5. The circuit of claim 4,

the first end of the SiC MOSFET is connected with the second end of the driving resistor;

and the second end of the SiC MOSFET is connected with the third end of the cut-off driving MOSFET.

6. The circuit of claim 1,

the external direct current voltage is 24V direct current voltage;

the voltage of the forward conduction narrow pulse train is 16V;

the voltage of the negative cut-off narrow pulse train is-16V;

when the modulation pulse is at a high level, the voltage is 15V;

when the modulation pulse is at a low level, the voltage is 0V;

the drive voltage of the SiC MOSFET is +16V and-3.9V.

Technical Field

The invention relates to the technical field of driving circuits. And more particularly to a SiC MOSFET drive circuit that isolates a 50kV high voltage.

Background

In recent years, the emergence of third generation semiconductor materials, represented by silicon carbide (SiC), has made it possible to greatly improve device performance, with SiC MOSFETs (metal oxide semiconductor field effect transistors) having faster switching speeds, higher switching frequencies, lower switching losses, and higher operating junction temperatures than Si IGBTs (insulated gate bipolar transistors). One development trend of the pulse power technology is to develop towards a fast pulse direction with a small front edge and a small back edge, and a SiC MOSFET is adopted in the high-voltage pulse modulator to replace a traditional Si IGBT, so that high-voltage modulation pulses with smaller waveform front edges and back edges and higher frequency can be generated, and the high-voltage pulse modulator has a wide application prospect. However, compared with the conventional Si IGBT, the driving positive voltage and negative voltage ranges of the SiC MOSFET are mostly asymmetric, and the floating operation is performed at a high voltage of several tens kV, which brings new design challenges to the driving circuit of the SiC MOSFET.

The SiC MOSFET driving circuit commonly used at present includes an active driving method and a passive driving method. The active driving mode adopts an optical fiber to transmit a modulation pulse signal, but cannot transmit driving voltage required by the SiC MOSFET, a high-voltage isolation power supply circuit needs to be additionally added, the circuit design is complex, meanwhile, when the multi-path SiC MOSFET is driven, the consistency of the optical fiber transmission signal must be strictly ensured, otherwise, the slowest conducting tube is broken down due to non-uniform voltage.

The traditional passive driving mode adopts a high-voltage driving pulse transformer for transmission, the driving voltage required by the SiC MOSFET can be transmitted while the modulation pulse signal information is transmitted, a high-voltage isolation power supply circuit is not arranged, the circuit design is simple, but the magnetic core of the transformer is easily saturated due to volt-second characteristics, and both wide pulses and narrow pulses cannot be considered.

Disclosure of Invention

The invention aims to provide a SiC MOSFET drive circuit for isolating a high voltage of 50 kV. To solve at least one of the problems of the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a SiC MOSFET driver circuit for isolating a 50kV high voltage, comprising:

the device comprises a pulse front-back edge generating circuit, a driving amplifying circuit, a high-voltage driving pulse transformer, a high-voltage side driving control circuit and a SiC MOSFET;

the pulse front and rear edge generating circuit is used for receiving external direct-current voltage and modulation pulse, generating a conduction narrow pulse string and a cut-off narrow pulse string, and sending the conduction narrow pulse string and the cut-off narrow pulse string to the driving amplifying circuit;

the drive amplifying circuit is used for receiving the conducting narrow pulse string and the stopping narrow pulse string, generating a positive conducting narrow pulse string and a negative stopping narrow pulse string and sending the positive conducting narrow pulse string and the negative stopping narrow pulse string to the high-voltage drive pulse transformer;

when the modulation pulse is at a high level, the high-voltage driving pulse transformer is used for sending the received forward conduction narrow pulse train to the high-voltage side driving control circuit;

when the modulation pulse is at a low level, the high-voltage driving pulse transformer is used for sending the received negative cut-off narrow pulse train to the high-voltage side driving control circuit;

the high-voltage side drive control circuit is used for converting the received positive-direction conduction narrow pulse string into a drive positive voltage of the SiC MOSFET and converting the received negative-direction cut-off narrow pulse string into a drive negative voltage of the SiC MOSFET, so that a SiC MOSFET drive voltage with the same width as the modulation pulse is generated.

In a specific embodiment, the duration of the conduction narrow pulse train is the same as the high level time of the modulation pulse;

the duration of the cut-off narrow pulse train is the same as the modulation pulse low level time.

In a specific embodiment, the output end of the pulse leading and trailing edge generating circuit is connected with the input end of the driving amplifying circuit;

the output end of the drive amplifying circuit is connected with the first end of the high-voltage drive pulse transformer;

the second end of the high-voltage driving pulse transformer is connected with the first end of the high-voltage side driving control circuit, and the third end of the high-voltage driving pulse transformer is connected with the second end of the high-voltage side driving control circuit;

the third end of the high-voltage side drive control circuit is connected with the first end of the SiC MOSFET;

and the fourth end of the high-voltage side drive control circuit is connected with the second end of the SiC MOSFET.

In one embodiment, the high side drive control circuit comprises: the driving circuit comprises a matching resistor, an 18V voltage stabilizing diode, a 3.9V voltage stabilizing diode, a 1.8V voltage stabilizing diode, a 5.1V voltage stabilizing diode, a conducting driving MOSFET, a cut-off driving MOSFET and a driving resistor;

the first end of the matching resistor is connected with the second end of the high-voltage driving pulse transformer and the cathode of the 18V voltage stabilizing diode;

the second end of the matching resistor is connected with the third end of the high-voltage driving pulse transformer and the cathode of the 3.9V voltage stabilizing diode;

the anode of the 18V voltage stabilizing diode is connected with the anode of the 3.9V voltage stabilizing diode;

the first end of the conduction driving MOSFET is connected with the cathode of the 18V voltage stabilizing diode, the second end of the conduction driving MOSFET is connected with the anode of the 1.8V voltage stabilizing diode, and the third end of the conduction driving MOSFET is connected with the cathode of the 5.1V voltage stabilizing diode and the first end of the driving resistor;

the first end of the cut-off driving MOSFET is connected with the cathode of the 3.9V voltage stabilizing diode and the cathode of the 1.8V voltage stabilizing diode, and the second end of the cut-off driving MOSFET is connected with the anode of the 5.1V voltage stabilizing diode.

In a specific embodiment, a first terminal of the SiC MOSFET is connected to a second terminal of the driving resistor;

and the second end of the SiC MOSFET is connected with the third end of the cut-off driving MOSFET.

In a specific embodiment, the external dc voltage is 24V dc voltage;

the voltage of the forward conduction narrow pulse train is 16V;

the voltage of the negative cut-off narrow pulse train is-16V;

when the modulation pulse is at a high level, the voltage is 15V;

when the modulation pulse is at a low level, the voltage is 0V;

the drive voltage of the SiC MOSFET is +16V and-3.9V.

The invention has the following beneficial effects:

the invention provides a SiC MOSFET drive circuit for isolating 50kV high voltage, which can provide normal drive voltage for a SiC MOSFET floating on 50kV high voltage, has good consistency, can give consideration to both wide pulse and narrow pulse, is suitable for complex modulation pulse waveform, does not have a high-voltage isolation power supply circuit, and has a simple circuit.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 shows a schematic diagram of a SiC MOSFET drive circuit isolating a 50kV high voltage, according to one embodiment of the invention;

description of the drawings: 1. the pulse front and back edge generating circuit 2, the driving amplifying circuit 3, the high-voltage driving pulse transformer 4, the matching resistor 5.18V voltage-stabilizing diode 6.3.9V voltage-stabilizing diode 7.1.8V voltage-stabilizing diode 8.5.1V voltage-stabilizing diode 9, the conducting driving MOSFET10, the cut-off driving MOSFET 11, the driving resistor 12, the SiC MOSFET 11

Detailed Description

In order to make the technical solutions and advantages of the present invention clearer, the following will describe embodiments of the present invention in further detail with reference to the accompanying drawings. Similar parts in the figures are denoted by the same reference numerals. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and is not to be taken as limiting the scope of the invention.

As shown in fig. 1, an embodiment of the present invention discloses a SiC MOSFET driving circuit for isolating a 50kV high voltage, including:

a pulse front and rear edge generating circuit 1, a drive amplifying circuit 2, a high-voltage drive pulse transformer 3, a high-voltage side drive control circuit 13 and a SiC MOSFET 12;

the pulse front and rear edge generating circuit is used for receiving external direct-current voltage and modulation pulse, generating a conduction narrow pulse string and a cut-off narrow pulse string, and sending the conduction narrow pulse string and the cut-off narrow pulse string to the driving amplifying circuit;

the drive amplifying circuit is used for receiving the conducting narrow pulse string and the stopping narrow pulse string, generating a positive conducting narrow pulse string and a negative stopping narrow pulse string and sending the positive conducting narrow pulse string and the negative stopping narrow pulse string to the high-voltage drive pulse transformer;

when the modulation pulse is at a high level, the high-voltage driving pulse transformer is used for sending the received forward conduction narrow pulse train to the high-voltage side driving control circuit;

when the modulation pulse is at a low level, the high-voltage driving pulse transformer is used for sending the received negative cut-off narrow pulse train to the high-voltage side driving control circuit;

the high-voltage side drive control circuit is used for converting the received positive-direction conduction narrow pulse string into a drive positive voltage of the SiC MOSFET and converting the received negative-direction cut-off narrow pulse string into a drive negative voltage of the SiC MOSFET, so that a SiC MOSFET drive voltage with the same width as the modulation pulse is generated.

In a specific embodiment, the output end of the pulse leading and trailing edge generating circuit is connected with the input end of the driving amplifying circuit;

the output end of the drive amplifying circuit is connected with the first end of the high-voltage drive pulse transformer;

the second end of the high-voltage driving pulse transformer is connected with the first end of the high-voltage side driving control circuit, and the third end of the high-voltage driving pulse transformer is connected with the second end of the high-voltage side driving control circuit;

the third end of the high-voltage side drive control circuit is connected with a gate G (namely the first end) of the SiC MOSFET;

the fourth terminal of the high-voltage side drive control circuit is connected to the source S (i.e., the second terminal) of the SiC MOSFET.

In one embodiment, the high side drive control circuit comprises: matching resistors 4, 18V zener diode 5, 3.9V zener diode 6, 1.8V zener diode 7, 5.1V zener diode 8, turn-on drive MOSFET9, turn-off drive MOSFET10, and drive resistor 11;

the first end of the matching resistor is connected with the second end of the high-voltage driving pulse transformer and the cathode of the 18V voltage stabilizing diode;

the second end of the matching resistor is connected with the third end of the high-voltage driving pulse transformer and the cathode of the 3.9V voltage stabilizing diode;

the anode of the 18V voltage stabilizing diode is connected with the anode of the 3.9V voltage stabilizing diode;

the source S (namely, the first end) of the conduction driving MOSFET is connected with the cathode of the 18V voltage stabilizing diode, the gate G (namely, the second end) is connected with the anode of the 1.8V voltage stabilizing diode, and the drain D (namely, the third end) is connected with the cathode of the 5.1V voltage stabilizing diode and the first end of the driving resistor;

the source S (i.e., the first terminal) of the off-drive MOSFET is connected to the cathode of the 3.9V zener diode and the cathode of the 1.8V zener diode, and the gate G (i.e., the second terminal) is connected to the anode of the 5.1V zener diode.

In one embodiment, the gate G (i.e., the first terminal) of the SiC MOSFET is connected to the second terminal of the driving resistor;

the source S (i.e., the second terminal) of the SiC MOSFET is connected to the drain D (i.e., the third terminal) of the off-drive MOSFET.

In this embodiment, when the driving circuit provided by the present invention works, an external dc 24V voltage is sent to the pulse front and back edge generating circuit 1 to provide a voltage required by the circuit work; external modulation pulses enter a pulse front-and-back edge generating circuit 1, a conducting narrow pulse string with a certain repetition frequency is generated by triggering on the rising front edge of the modulation pulses, the duration time is the same as the high level time of the modulation pulses, a stopping narrow pulse string with a certain repetition frequency is generated by triggering on the falling back edge of the modulation pulses, and the duration time is the same as the low level time of the modulation pulses; after the conducting narrow pulse string and the stopping narrow pulse string pass through the driving amplifying circuit 2, a 16V positive direction conducting narrow pulse string and a-16V negative direction stopping narrow pulse string are generated and transmitted to the secondary side of the high-voltage driving pulse transformer 3 after passing through the high-voltage driving pulse transformer 3; the matching resistor 4 is used to match the secondary impedance of the high-voltage drive pulse transformer 3.

When the modulation pulse is at a high level of 15V, the secondary output of the high-voltage driving pulse transformer 3 is used for conducting the narrow pulse train in the forward direction; when the narrow pulse is 16V, the 18V zener diode 5 is turned off in the reverse direction, the inter-GS driving voltage for turning on the driving MOSFET9 is-16V and is in the off state, the inter-GS driving voltage for turning off the driving MOSFET10 is 10V and is in the on state, the pulse energy charges the inter-GS junction capacitor of the SiC MOSFET 12 through the body diode of the on driving MOSFET9, the driving resistor 11 and the off driving MOSFET10, and the 16V voltage is generated between GS of the SiC MOSFET 12; when the narrow pulse is 0V, the 1.8V zener diode 7 is turned off in the reverse direction to suppress the negative overshoot voltage of the high voltage drive pulse transformer 3, so that the on drive MOSFET9 is reliably turned off, and the 16V voltage is maintained between GS of the SiC MOSFET 12; when the narrow pulse is 16V again, the junction capacitor between GS of the SiC MOSFET 12 is charged again, so that GS voltage of the SiC MOSFET 12 keeps 16V during the period that the modulation pulse is at high level, and the SiC MOSFET 12 is conducted;

when the modulation pulse is at a low level of 0V, the secondary output of the high-voltage driving pulse transformer 3 is negatively cut off the narrow pulse train; when the narrow pulse is-16V, the 3.9V voltage stabilizing diode 6 clamps the narrow pulse amplitude to-3.9V, the GS interval driving voltage of the cut-off driving MOSFET10 is-3.9V and is in a cut-off state, the GS interval driving voltage of the conduction driving MOSFET9 is 2V and is in a conduction state, the pulse energy charges the GS interval junction capacitor of the SiC MOSFET 12 through the body diode of the cut-off driving MOSFET10, the driving resistor 11 and the conduction driving MOSFET9, and the GS interval of the SiC MOSFET 12 generates-3.9V voltage; when the narrow pulse is 0V, the 5.1V voltage stabilizing diode 8 is cut off reversely, the forward overshoot voltage of the high-voltage driving pulse transformer 3 is restrained, the cut-off driving MOSFET10 is reliably cut off, and the voltage of-3.9V is maintained between GS of the SiC MOSFET 12; when the narrow pulse is-16V again, the junction capacitor between GS of the SiC MOSFET 12 is charged, so that GS voltage of the SiC MOSFET 12 keeps-3.9V during the period that the modulation pulse is at low level, and the SiC MOSFET 12 is cut off;

the drive circuit generates SiC MOSFET drive voltage with positive and negative amplitudes of +16V/-3.9V and the same width as the modulation pulse;

the invention provides a SiC MOSFET drive circuit for isolating 50kV high voltage, which can provide normal drive voltage for a SiC MOSFET floating on 50kV high voltage, has good consistency, can give consideration to both wide pulse and narrow pulse, is suitable for complex modulation pulse waveform, does not have a high-voltage isolation power supply circuit, and has a simple circuit.

It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention, and it will be obvious to those skilled in the art that other variations or modifications may be made on the basis of the above description, and all embodiments may not be exhaustive, and all obvious variations or modifications may be included within the scope of the present invention.