阅读说明：本技术 基于碳化硅mosfet模块的大功率高功率密度变流器及结构 (High-power-density converter and structure based on silicon carbide MOSFET module ) 是由 原熙博 李炎 张永磊 张雷 徐一埔 叶飞 李哲 李耀华 王子建 于 2020-05-22 设计创作，主要内容包括：本发明公开了一种基于碳化硅MOSFET模块的大功率高功率密度变流器及结构,适用于电力电子技术领域。包括五台三相DC/AC变流器、直流汇流母排和交流汇流母排；五台三相DC/AC变流器顺序编号,五台三相DC/AC变流器的直流侧通过两根直流汇流母排与直流电源或电池连接；五台三相DC/AC变流器的交流侧通过三根交流汇流母排与三相电网或三相负载连接。其能够实现直流到交流、交流到直流的能量双向流动。系统整体结构依托碳化硅MOSFET的特性,可实现系统整体的高功率密度设计。(The invention discloses a high-power-density converter and a structure based on a silicon carbide MOSFET module, which are suitable for the technical field of power electronics. The three-phase DC/AC converter comprises five three-phase DC/AC converters, a direct current bus bar and an alternating current bus bar; the five three-phase DC/AC converters are numbered in sequence, and the direct current sides of the five three-phase DC/AC converters are connected with a direct current power supply or a battery through two direct current bus bars; and the alternating current sides of the five three-phase DC/AC converters are connected with a three-phase power grid or a three-phase load through three alternating current bus bars. The bidirectional energy flow from direct current to alternating current and from alternating current to direct current can be realized. The whole structure of the system relies on the characteristics of the silicon carbide MOSFET, and the high-power density design of the whole system can be realized.)

1. A high-power-density current transformer based on a silicon carbide MOSFET module is characterized in that: the three-phase DC/AC converter comprises five three-phase DC/AC converters (2), a direct current bus bar (4) and an alternating current bus bar (5); five three-phase DC/AC converters (2) are numbered in sequence, and the direct current sides of the five three-phase DC/AC converters (2) are connected with a direct current power supply or a battery (1) through two direct current bus bars (4); the alternating current side of the five three-phase DC/AC converters (2) is connected with a three-phase power grid or a three-phase load (3) through three alternating current bus bars (5);

the three-phase DC/AC converter comprises a three-phase two-level half-bridge circuit and a controller (12), wherein the three-phase two-level half-bridge circuit consists of three half-bridge silicon carbide MOSFET power modules (6), each half-bridge silicon carbide MOSFET power module (6) is connected with and driven by a power module driving board (7), the three power module driving boards (7) are respectively connected with the controller (12) through optical fibers, and the controller (12) generates driving signals and finally acts on the half-bridge silicon carbide MOSFET power modules (6) to control the on and off of the half-bridge silicon carbide MOSFET power modules;

three half-bridge silicon carbide MOSFET power modules are connected in parallel through a positive P pole and a negative N pole, the three half-bridge silicon carbide MOSFET power modules are further connected with a direct current side supporting capacitor part (8) and a direct current output terminal (13) in parallel, the positive P pole and the negative N pole of the direct current side supporting capacitor part (8) are connected with the positive P pole and the negative N pole of the direct current output terminal (13), and u on an alternating current output terminal (14)_a、u_b、u_cThe phases are respectively connected with the alternating current output ports of the three half-bridge silicon carbide MOSFET power modules through A, B, C three-phase filter inductors; A. b, C three-phase filter inductor and three half-bridge silicon carbide MOSFET power module AC output port are respectively provided with three AC current sensors (10), the three AC current sensors (10) are connected with the controller (12) through AC current sampling lines, the AC current sensors (10) transmit weak current signals to the controller (12) through cables, and u on the AC output terminal (14)_a、u_b、u_cThe circuit between the filter inductance of looks and A, B, C threephase is connected to voltage sampling board (11) through three alternating voltage sampling lines respectively on, is equipped with two direct voltage sampling lines on positive P utmost point and the negative N pole of direct current output terminal (13) and is connected with voltage sampling board (11), and voltage sampling board (11) are connected with controller (12), and direct current side voltage, the side voltage signal of alternating current are gathered through the cable to voltage sampling board (11) to transmit weak current signal to controller (12).

2. The high power density current transformer based on silicon carbide MOSFET module as claimed in claim 1, wherein: the five three-phase DC/AC converters (2) are numbered in sequence, controllers (12) are arranged on the three-phase DC/AC converter numbered as No. 1 and the three-phase DC/AC converter numbered as No. 3, and the two controllers (12) jointly form a control system of the high-power and high-power density converter based on the silicon carbide MOSFET; the controller (12) in the No. 1 three-phase DC/AC converter is a master controller, and the controller (12) in the No. 3 converter is a slave controller. The hardware structures of the master controller and the slave controller are consistent, and only the functions are inconsistent; a main controller: the system is responsible for control calculation, signal transmission and synchronization of the whole system, and is also responsible for sampling of direct current voltage and alternating current voltage, current sampling of No. 1 and No. 2 converters, pulse signal sending and error signal detection; from the controller: the device is responsible for current sampling, pulse signal sending and error signal detection of No. 3, No. 4 and No. 5 three-phase DC/AC converters.

3. The high power density current transformer based on silicon carbide MOSFET module as claimed in claim 1, wherein: the controller (12) comprises a DSP chip, an FPGA chip and a sampling chip, wherein the DSP chip, the FPGA chip and the sampling chip form a data interconnection line relationship for data and signal transmission through 16 data buses and 16 data address buses, the sampling chip is connected with 12 sampling channels and used for collecting voltage and current signals, the FPGA chip is also connected with 24 optical fiber output ports and 12 optical fiber input ports through lines respectively and used for sending pulse signals to a power module driving plate (7) in the converter, receiving error signals of the power module driving plate (7) and bearing tasks of communication between master and slave controllers, and the FPGA chip is also connected with 6I/O ports and used for receiving trigger signals of an operation control button.

4. The high power density current transformer based on silicon carbide MOSFET module as claimed in claim 3, wherein: the model of the DSP chip is TI F28335, the model of the FPGA chip is XILINX SPARTAN3 series, and the model of the sampling chip is AD 7656.

5. The high power density current transformer based on silicon carbide MOSFET module as claimed in claim 1, wherein: the direct current side supporting capacitor part (8) of the single three-phase DC/AC converter (2) adopts a structure of a direct current laminated busbar (16) to respectively connect the positive P and negative N poles of three silicon carbide MOSFET power modules (6) in parallel, a direct current supporting capacitor (15) and a direct current absorption capacitor (17) are connected between the positive pole and the negative pole of the direct current laminated busbar (16) in parallel, the direct current laminated busbar (16) reduces parasitic parameters on the direct current side, the direct current supporting capacitor (15) mainly plays a role in supporting voltage on the direct current side, and the direct current absorption capacitor (17) is placed near the silicon carbide MOSFET power modules (6) and used for further reducing the parasitic parameters at the interface; the direct current support capacitor (15) and the direct current absorption capacitor (17) are in a dispersed design, and the direct current support capacitor (15) and the direct current absorption capacitor (17) are embedded above each silicon carbide MOSFET power module (6), so that parasitic parameters can be reduced, and the internal space of the equipment can be reasonably utilized.

6. A three-phase DC/AC converter architecture for use with a high power density converter based on silicon carbide MOSFET modules as claimed in claim 1 wherein: the power module comprises a power module driving board (7) with a rectangular structure, the power module driving board (7) is inserted on three silicon carbide MOSFET power modules (6) which are transversely arranged, a radiator (19) is arranged below the silicon carbide MOSFET power modules (6), the three silicon carbide MOSFET power modules (6) are respectively connected with three alternating current busbars (18), three direct current supporting capacitors (15) and three direct current absorbing capacitors (17) which are connected in parallel are arranged above the silicon carbide MOSFET power modules (6) through direct current laminated busbars (16), one side of the radiator (19) is connected with three radiating fans (20) through a radiating fan structure panel (21), an alternating current induction PCB (26) is arranged on the other side of the radiator (19), the alternating current induction PCB (26) is mutually connected with the alternating current busbars (18) through screws, three groups of nine alternating current inductors (9) are arranged on the alternating current busbars (18), an alternating current sensing upper structural part (23) is arranged above the alternating current sensing (9), three switching power supplies (24) are arranged on the alternating current sensing upper structural part (23), a switching power supply upper structural part (25) is arranged on the three switching power supplies (24), and a voltage sensing sampling plate (11) and a controller (12) are arranged at the top of the switching power supply upper structural part (25).

7. A three-phase DC/AC converter architecture as claimed in claim 6, characterized in that: the filter inductor at the alternating current side of the single three-phase DC/AC converter (2) is a single L filter and is placed in a dispersed mode, the filter inductor at each phase of A, B, C three phases is formed by connecting three alternating current inductors (9) in parallel and is connected through an alternating current inductor PCB (26), and the alternating current inductors are placed at the rear end of a radiator (19) and are positioned at the tail end of an air duct of the converter, so that the heat dissipation of the alternating current inductors is facilitated.

8. A three-phase DC/AC converter architecture as claimed in claim 6, characterized in that: the radiator (19), the alternating current inductor (9) and the alternating current busbar (18) are arranged in an air channel formed by a radiator structure panel (21), a radiating fan structural member (22), an alternating current inductor upper structural member (23) and a converter shell, and three radiating fans (20) are arranged at one end of the air channel to perform forced air cooling current conversion. The design mode can concentrate the heating elements in the equipment in the air duct, and is convenient for heat dissipation of the system.

Technical Field

The invention designs a high-power-density converter and a structure based on a silicon carbide MOSFET module, and belongs to the technical field of power electronics.

Background

With the increasingly prominent global energy crisis and environmental problems, the development of power electronic technology brings a new opportunity for solving the energy problems. Due to the explosion of new energy distributed power generation and the demand of more application scenes, power electronic equipment is developed towards the direction of high power, light weight and high power density. The development of traditional industries, such as the development of the industries of multi-electric airplanes and electric automobiles, also puts higher requirements on the volume and the power density of the converter, and uses an electric driving system to replace a hydraulic and pneumatic driving system which is used in a large amount. How to make power electronic equipment have high efficiency while having high power density is also a hot spot of research in the power electronic industry at present. The converter adopting the traditional silicon-based device has a large proportion of passive devices in the volume of a system due to the limitation of switching frequency, so that the requirement of high power density cannot be realized, and the volume of the air-cooled high-power converter adopting the silicon-based device is about 0.3MW/m 3. Due to the superiority of materials of wide-bandgap power devices, the wide-bandgap power devices are in the way of meeting the needs of the power electronics industry. The equipment volume of the converter adopting the wide-bandgap power device under the same power and loss is far smaller than that of the traditional silicon IGBT converter.

At present, power electronic devices are limited by voltage resistance, power level and switching frequency, and under the application occasion of high power, the power output capability of a system is improved by adopting a series-parallel connection mode. Complex system structures, variable control methods and the like all present a serious challenge to high-power electronic equipment to achieve high efficiency and high power density. At the beginning of equipment design, comprehensive consideration should be given to device type selection, a heat dissipation system, an equipment structure and the like so as to achieve the optimal power density. And the circulation phenomenon which inevitably occurs between the current transformer and between the devices is also a problem to be considered.

The invention content is as follows:

the invention solves the problems that: aiming at the defects of the technology, the high-power-density converter based on the silicon carbide MOSFET module and the structure thereof are provided, wherein the high-power-density converter is simple in structure and good in using effect, and can inhibit the circulating current problem of the parallel converter with a multi-controller structure while improving the power density of high-power equipment.

In order to achieve the technical purpose, the high-power-density converter based on the silicon carbide MOSFET module comprises five three-phase DC/AC converters, a direct current bus bar and an alternating current bus bar; the five three-phase DC/AC converters are numbered in sequence, and the direct current sides of the five three-phase DC/AC converters are connected with a direct current power supply or a battery through two direct current bus bars; the alternating current sides of the five three-phase DC/AC converters are connected with a three-phase power grid or a three-phase load through three alternating current bus bars;

the three-phase DC/AC converter comprises a three-phase two-level half-bridge circuit and a controller, wherein the three-phase two-level half-bridge circuit consists of three half-bridge silicon carbide MOSFET power modules, each half-bridge silicon carbide MOSFET power module is connected with and driven by a power module driving board, the three power module driving boards are respectively connected with the controller through optical fibers, and the controller generates driving signals and finally acts on the half-bridge silicon carbide MOSFET power modules to control the on and off of the half-bridge silicon carbide MOSFET power modules;

three half-bridge silicon carbide MOSFET power modules are connected in parallel through a positive P pole and a negative N pole, and are also connected with a direct current in parallelA side supporting capacitor part and a DC output terminal, wherein the positive P pole and the negative N pole of the DC side supporting capacitor part are connected with the positive P pole and the negative N pole of the DC output terminal, and u on the AC output terminal_a、u_b、u_cThe phases are respectively connected with the alternating current output ports of the three half-bridge silicon carbide MOSFET power modules through A, B, C three-phase filter inductors; A. b, C three-phase filter inductor and three half-bridge silicon carbide MOSFET power module, three AC current sensors are respectively arranged on the lines between the AC output ports, the three AC current sensors are connected with the controller through AC current sampling lines, the AC current sensors transmit weak current signals to the controller through cables, and u on the AC output terminals_a、u_b、u_cThe circuit between the filter inductor of the three-phase and A, B, C is connected to a voltage sampling plate through three alternating voltage sampling lines, two direct voltage sampling lines are arranged on the positive P pole and the negative N pole of the direct current output terminal and connected with the voltage sampling plate, the voltage sampling plate is connected with a controller, and the voltage sampling plate acquires direct current side voltage and alternating current side voltage signals through a cable and transmits weak current signals to the controller.

The five three-phase DC/AC converters are numbered in sequence, controllers are arranged on the three-phase DC/AC converter No. 1 and the three-phase DC/AC converter No. 3, and the two controllers jointly form a control system of the high-power-density converter based on the silicon carbide MOSFET; the controller in the No. 1 three-phase DC/AC converter is a master controller, and the controller in the No. 3 converter is a slave controller. The hardware structures of the master controller and the slave controller are consistent, and only the functions are inconsistent; a main controller: the system is responsible for control calculation, signal transmission and synchronization of the whole system, and is also responsible for sampling of direct current voltage and alternating current voltage, current sampling of No. 1 and No. 2 converters, pulse signal sending and error signal detection; from the controller: the device is responsible for current sampling, pulse signal sending and error signal detection of No. 3, No. 4 and No. 5 three-phase DC/AC converters.

The controller comprises a DSP chip, an FPGA chip and a sampling chip, wherein the three chips of the DSP chip, the FPGA chip and the sampling chip form a line relation of mutual data connection of the three chips through 16 data buses and 16 data address buses for data and signal transmission, the sampling chip is connected with 12 sampling channels for collecting voltage and current signals, the FPGA chip is also respectively connected with 24 optical fiber output ports and 12 optical fiber input ports through lines for sending pulse signals to a power module driving plate in the converter, receiving error signals of the power module driving plate and bearing the task of communication between master and slave controllers, and the FPGA chip is also connected with 6I/O ports for receiving trigger signals of an operation control button.

The model of the DSP chip is TI F28335, the model of the FPGA chip is XILINX SPARTAN3 series, and the model of the sampling chip is AD 7656.

The direct-current side supporting capacitor part of the single three-phase DC/AC converter adopts a direct-current laminated busbar structure to connect the positive P and negative N poles of three silicon carbide MOSFET power modules in parallel respectively. A direct current supporting capacitor and a direct current absorbing capacitor are connected in parallel between the positive electrode and the negative electrode of the direct current laminated busbar, the direct current laminated busbar reduces parasitic parameters on the direct current side, the direct current supporting capacitor mainly plays a role of supporting voltage on the direct current side, and the direct current absorbing capacitor is placed near the silicon carbide MOSFET power module and used for further reducing the parasitic parameters at an interface; the direct current support capacitor and the direct current absorption capacitor are in a dispersed design, and the direct current support capacitor and the direct current absorption capacitor are embedded above each silicon carbide MOSFET power module, so that parasitic parameters can be reduced, and the internal space of the equipment can be reasonably utilized.

A three-phase DC/AC converter comprises a power module driving board with a rectangular structure, wherein the power module driving board is inserted on three silicon carbide MOSFET power modules which are transversely arranged, a radiator is arranged below the silicon carbide MOSFET power modules, the three silicon carbide MOSFET power modules are respectively connected with three alternating current busbars, three direct current supporting capacitors and three direct current absorbing capacitors which are connected in parallel are arranged above the silicon carbide MOSFET power modules through direct current laminated busbars, one side of the radiator is connected with three radiating fans through a radiating fan structure panel, the other side of the radiator is provided with an alternating current inductive PCB, the alternating current inductive PCB is mutually connected with the alternating current busbars through screws, three groups of nine alternating current inductors are arranged on the alternating current busbars, an alternating current inductive upper structural part is arranged above the alternating current inductors, three switching power supplies are arranged on the alternating current inductive upper structural part, and switching power supply upper structural parts are arranged on the, and a voltage transmission sampling plate and a controller are arranged at the top of the upper structural part of the switching power supply.

The filter inductor on the alternating current side of the single three-phase DC/AC converter is a single L filter and is placed in a dispersed mode, the filter inductor on each phase of A, B, C three phases is formed by connecting three alternating current inductors in parallel and is connected through an alternating current inductor PCB, the alternating current inductors are placed at the rear end of the radiator and are positioned at the tail end of the converter air duct, and heat dissipation of the alternating current inductors is facilitated.

The radiator, the alternating current inductor and the alternating current busbar are arranged in an air channel formed by a radiator structure panel, a radiating fan structural member, an alternating current inductor upper structural member and a converter shell, and three radiating fans are arranged at one end of the air channel to perform forced air cooling current conversion. The design mode can concentrate the heating elements in the equipment in the air duct, and is convenient for heat dissipation of the system.

Has the advantages that:

aiming at the problems of low power density and the like of the existing high-power converter equipment, the invention redesigns the integral structure of the equipment, greatly reduces the volume of the equipment while realizing high efficiency of the output power of a high-power converter system, does not need to increase the design cost when a plurality of converters are stacked, can realize flexible stacking of integral power output, and can realize 1.246MW/m by taking the high-power converter equipment formed by connecting 5 three-phase DC/AC converters in parallel as an example³The power density of the inverter exceeds 98 percent, and the inverter has simple structure, good practical effect and wide practicability.

Description of the drawings:

FIG. 1 is a schematic diagram of a topology of a high power converter according to the present invention;

FIG. 2 is a schematic circuit diagram of a single three-phase DC/AC converter according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a control system according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a controller according to an embodiment of the present invention;

FIG. 5(a) is a schematic structural diagram of a single three-phase DC/AC converter in an embodiment of the present invention;

FIG. 5(b) is a schematic structural diagram of a single three-phase DC/AC converter in an embodiment of the present invention;

FIG. 5(c) is a schematic structural diagram of a single three-phase DC/AC converter in an embodiment of the present invention;

FIG. 5(d) is a schematic diagram of a single three-phase DC/AC converter according to an embodiment of the present invention;

FIG. 5(e) is a schematic structural diagram of a single three-phase DC/AC converter according to an embodiment of the present invention;

fig. 5(f) is a schematic structural diagram of a single three-phase DC/AC converter in the embodiment of the present invention.

In the figure: 1-a direct current power supply or battery, 2-a three-phase DC/AC converter, 3-a three-phase power grid or three-phase load, 4-a direct current bus bar, 5-an alternating current bus bar, 6-a silicon carbide MOSFET power module, 7-a power module driving board, 8-a direct current side supporting capacitor part, 9-an alternating current inductor, 10-a current sensor, 11-a voltage sampling board, 12-a controller, 13-a direct current output terminal, 14-an alternating current output terminal, 15-a direct current supporting capacitor, 16-a direct current laminated bus bar, 17-a direct current absorbing capacitor, 18-an alternating current bus bar, 19-a radiator, 20-a radiator fan, 21-a radiator structure panel, 22-a radiator fan structure, 23-an alternating current inductor upper structure, 24-switching power supply, 25-switching power supply upper structure and 26-alternating current induction PCB.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.

As shown in fig. 1, the high-power-density converter based on the silicon carbide MOSFET module of the present invention includes five three-phase DC/AC converters 2, a DC bus bar 4 and an AC bus bar 5; the five three-phase DC/AC converters 2 are numbered sequentially, and the direct current sides of the five three-phase DC/AC converters 2 are connected with a direct current power supply or a battery 1 through two direct current bus bars 4; the alternating current side of the five three-phase DC/AC converters 2 is connected with a three-phase power grid or a three-phase load 3 through three alternating current bus bars 5;

as shown in fig. 2, the three-phase DC/AC converter includes a three-phase two-level half-bridge circuit composed of three half-bridge silicon carbide MOSFET power modules 6 and a controller 12, each half-bridge silicon carbide MOSFET power module 6 is connected with and driven by a power module drive board 7, the three power module drive boards 7 are respectively connected with the controller 12 through optical fibers, and the controller 12 generates a drive signal and finally acts on the half-bridge silicon carbide MOSFET power module 6 to control the on/off of the power module;

three half-bridge silicon carbide MOSFET power modules are connected in parallel through a positive P pole and a negative N pole, the three half-bridge silicon carbide MOSFET power modules are further connected with a direct current side supporting capacitor part 8 and a direct current output terminal 13 in parallel, the positive P pole and the negative N pole of the direct current side supporting capacitor part 8 are connected with the positive P pole and the negative N pole of the direct current output terminal 13, and u poles on an alternating current output terminal 14_a、u_b、u_cThe phases are respectively connected with the alternating current output ports of the three half-bridge silicon carbide MOSFET power modules through A, B, C three-phase filter inductors; A. b, C three-phase filter inductor and three AC current sensors 10 are respectively arranged on the lines between the AC output ports of the three half-bridge silicon carbide MOSFET power modules, the three AC current sensors 10 are connected with the controller 12 through AC current sampling lines, the AC current sensors 10 transmit weak current signals to the controller 12 through cables, and u on the AC output terminal 14_a、u_b、u_cThe circuit between the filter inductor of three-phase and A, B, C is connected to the voltage sampling board 11 through three alternating voltage sampling lines respectively, and positive P utmost point and the negative N utmost point of direct current output terminal 13 are equipped with two direct voltage sampling lines and are connected with voltage sampling board 11, and voltage sampling board 11 is connected with controller 12, and voltage sampling board 11 gathers direct current side voltage, alternating current side voltage signal through the cable to weak current signal transmission for controller 12.

As shown in fig. 3, the five three-phase DC/AC converters 2 are numbered in sequence, and controllers 12 are arranged on the three-phase DC/AC converter No. 1 and the three-phase DC/AC converter No. 3, and the two controllers 12 jointly form a control system of a high-power and high-power density converter based on a silicon carbide MOSFET; the controller 12 in the No. 1 three-phase DC/AC converter is a master controller, and the controller 12 in the No. 3 converter is a slave controller. The hardware structures of the master controller and the slave controller are consistent, and only the functions are inconsistent; a main controller: the system is responsible for control calculation, signal transmission and synchronization of the whole system, and is also responsible for sampling of direct current voltage and alternating current voltage, current sampling of No. 1 and No. 2 converters, pulse signal sending and error signal detection; from the controller: the device is responsible for current sampling, pulse signal sending and error signal detection of No. 3, No. 4 and No. 5 three-phase DC/AC converters.

As shown in fig. 4, the controller 12 includes a DSP chip, an FPGA chip, and a sampling chip, wherein the three chips of the DSP chip, the FPGA chip, and the sampling chip form a line relationship of data interconnection among the three chips through 16 data buses and 16 data address buses for transmission of data and signals, the sampling chip is connected with 12 sampling channels for collecting voltage and current signals, the FPGA chip is further connected with 24 optical fiber output ports and 12 optical fiber input ports through lines, respectively, for sending a pulse signal to the power module drive board 7 in the converter, receiving an error signal of the power module drive board 7, and also taking a task of communication between the master and slave controllers, and the FPGA chip is further connected with 6I/O ports for receiving a trigger signal for operating a control button; the model of the DSP chip is TI F28335, the model of the FPGA chip is XILINX SPARTAN3 series, and the model of the sampling chip is AD 7656.

The direct current side support capacitor part 8 of the single three-phase DC/AC converter 2 adopts a direct current laminated busbar 16 structure to respectively connect the positive P and negative (N) poles of the three silicon carbide MOSFET power modules 6 in parallel. A direct current supporting capacitor 15 and a direct current absorbing capacitor 17 are connected in parallel between the positive electrode and the negative electrode of the direct current laminated busbar 16, the direct current laminated busbar 16 reduces parasitic parameters on the direct current side, the direct current supporting capacitor 15 mainly plays a role in supporting voltage on the direct current side, and the direct current absorbing capacitor 17 is placed near the silicon carbide MOSFET power module 6 and used for further reducing the parasitic parameters at the interface; the direct current support capacitor 15 and the direct current absorption capacitor 17 are in a dispersed design, and the direct current support capacitor 15 and the direct current absorption capacitor 17 are embedded above each silicon carbide MOSFET power module 6, so that parasitic parameters can be reduced, and the internal space of the equipment can be reasonably utilized.

As shown in fig. 5(a) to 5(f), a three-phase DC/AC converter structure used for a high-power-density converter based on silicon carbide MOSFET modules comprises a power module driving board 7 with a rectangular structure, the lower part of the power module driving board 7 is inserted into three silicon carbide MOSFET power modules 6 arranged transversely, a heat sink 19 is arranged below the silicon carbide MOSFET power modules 6, the three silicon carbide MOSFET power modules 6 are respectively connected with three AC busbars 18, three DC supporting capacitors 15 and three DC absorbing capacitors 17 connected in parallel are arranged above the silicon carbide MOSFET power modules 6 through a DC laminated busbar 16, one side of the heat sink 19 is connected with three cooling fans 20 through a cooling fan structure panel 21, the other side of the heat sink 19 is provided with an AC inductive PCB26, and the AC inductive PCB26 is connected with the AC busbars 18 through screws, be equipped with nine alternating current inductance 9 of three a set of totally on the female 18 that exchanges, alternating current inductance 9 top is equipped with alternating current inductance upper portion structure 23, is equipped with three switching power supply 24 on the alternating current inductance upper portion structure 23, is equipped with switching power supply upper portion structure 25 on the three switching power supply 24, and switching power supply upper portion structure 25 top is equipped with voltage sensing sampling board 11 and controller 12.

The filter inductor on the alternating current side of the single three-phase DC/AC converter 2 is a single L filter and is placed in a dispersed mode, the filter inductor on each phase of A, B, C three phases is formed by connecting three alternating current inductors 9 in parallel and is connected through an alternating current inductor PCB26, and the alternating current inductors are placed at the rear end of the radiator 19 and at the tail end of an air duct of the converter, so that heat dissipation of the alternating current inductors is facilitated.

The radiator 19, the alternating current inductor 9 and the alternating current busbar 18 are arranged in an air channel formed by a radiator structure panel 21, a radiating fan structural member 22, an alternating current inductor upper structural member 23 and a converter shell, the structural member and the shell are tightly fixed together through screws, and three radiating fans 20 are arranged at one end of the air channel for forced air cooling current conversion. The design mode can concentrate the heating elements in the equipment in the air duct, and is convenient for heat dissipation of the system.

The direct current side is a direct current power supply, and the alternating current side is an embodiment working mode of a three-phase alternating current power grid:

a, connecting a direct current side bus bar interface with a direct current power supply or a battery 1, connecting an alternating current side bus bar with a three-phase power grid or a three-phase load 3 through an alternating current contactor, and checking whether reliable connection exists;

b, the control system formed by the control device 12 is powered on, the front panel power-on indicator lights are turned on, the heat radiation fan 20 starts working, and fan sound is generated at the moment.

c, detecting voltage and current, and waiting for a starting command state;

d, turning on a direct-current power supply or a battery 1, adjusting the voltage of a direct-current side to 650V, connecting and conducting an alternating-current side busbar 4 with a three-phase power grid or a three-phase load 3, and observing whether the condition of the alternating-current voltage reaches 380V; if the requirements of direct current and alternating current voltage are met, the next step is carried out; if the requirements are not met, the alternating current contactor, the direct current power supply and the shutdown power-off detection problem need to be closed;

e, if the requirement of the previous step is met, starting normal work and carrying out inversion;

if the machine is required to be stopped, the power supply is cut off, and the equipment stops working at the moment; then the AC contactor is turned off, and the connection between the AC busbar 4 and a three-phase power grid or a three-phase load 3 is cut off; and turning off the direct current power supply and waiting for the direct current voltage to recover to 0V.

g, after confirming that the strong current is cut off again, the control system is powered off, and at the moment, the front panel indicator light is turned off. The ready, start, stop buttons are restored.

h, finishing the starting and stopping processes.