KR102114717B1 - SiC INVERTER DEVICE - Google Patents

Abstract

The present invention relates to a silicon carbide (SiC) inverter device, a SiC switching module, a DC link capacitor disposed on the top of the SiC switching module, a gate driver disposed on the side of the SiC switching module, the SiC switching module and the DC It includes a DC link busbar directly connecting the link capacitor and a fixing bracket for fixing the gate driver to the side of the SiC switching module. Therefore, the present invention proposes a structure capable of maximizing the performance of a SiC inverter that speeds up switching speed and minimizes switching losses.

Description

SiC inverter device {SiC INVERTER DEVICE}

The present invention relates to a silicon carbide (SiC) inverter technology, and more particularly, to a SiC inverter device having a structure capable of maximizing the performance of a SiC inverter that speeds up switching speed and minimizes switching loss.

SiC (Silicon Carbide) semiconductors are superior in heat resistance and withstand voltage compared to silicon (Si), which is commonly used in device fabrication, to realize high performance and low power consumption for inverter devices, household power modules, and automotive power semiconductor devices. We are raising expectations with promising ingredients that we can. Silicon carbide, the most widely known semiconductor material, is a material in which silicon and carbon are combined in a 1: 1 ratio, and its hardness is second to diamond due to its strong covalent bond, and has been used as a sandpaper material since the late 19th century. Silicon carbide was first prepared synthetically before being found in nature, and is very rarely observed in nature. Silicon carbide as a semiconductor, in the 1950's, silicon and germanium, along with many studies have been conducted in the early stages of semiconductor research, but it is difficult to produce large single crystals and wafers, such as silicon semiconductors, and has not been noticed for a while. Therefore, until recent years, it has been used more as a sintered body for manufacturing high-strength materials than in applications as semiconductor materials. Since the 1980s, a single crystal growth method capable of manufacturing semiconductor devices has been developed, and has been spotlighted as a next-generation semiconductor material. Silicon carbide has superior electrical and mechanical thermal properties and superior chemical and mechanical stability compared to conventional silicon, making it the most applicable material for next-generation semiconductor materials, especially high-voltage, high-power, and high-temperature semiconductor materials. Depending on the type of SiC, the band gap is distributed from 2.2eV to 3.3eV, and mainly used 4H-SiC and 6H-SiC are 3.0eV to 3.3eV, which is three times that of Si, and wide band gap such as GaN, ZnO, AlN, etc. Corresponds to the material. In addition, the critical electric field is 10 times that of Si and the thermal conductivity is 3 times. In addition, it is chemically stable and resistant to radiation, making it suitable for manufacturing semiconductor devices that operate in special environments. It is suitable as a high output power device ranging from 1 kV to 100 kV due to its high critical electric field value and thermal conductivity, and is an optimal material as a power device for high temperature (operable up to 500 to 700 ° C) due to its wide band gap and high thermal conductivity characteristics.

The SiC switching device is a next-generation power device characterized by low loss and high speed switching. However, high-speed switching increases the parasitic inductance component and increases the spike voltage of the output voltage according to the structure of the power converter, so that the switching element may be burned out if the spike voltage exceeds the breakdown voltage of the module.

Korean Patent Publication No. 10-2015-0121988 (2015.10.30) includes a base plate, a direct bonded copper (DBC) substrate bonded to the base plate, an extended silicon carbide (SiC) chip bonded to the top of the DBC substrate, and a DBC substrate. It includes a bonding wire that electrically connects the expanded silicon carbide chip. In the expanded silicon carbide chip, at least four unit chips are bonded to each other in a square shape without gaps, and each unit chip has a source, a drain, and a gate individually. .

Korean Patent Publication No. 10-2011-0078962 (2011.07.07) is provided with an LC filter unit 110 for filtering DC power. In addition, an inverter unit 120 including full-bridge switching elements sw1 to sw4 that is switched to switch the filtered DC power to AC power is provided. The switching elements sw1 to sw4 have a structure in which transistors and diodes are configured in parallel. Here, the diode is a diode having a capacity larger than the transient voltage generated when the switching elements sw1 to sw4 are switched, and is composed of a silicon carbide (SiC) Schottky barrier diode. According to the present invention, the silicon carbide Schottky barrier diode can protect the transistor from being deteriorated or damaged by noise generated when the switching elements sw1 to sw4 are switched, and is configured in a conventional inverter device. The old snubber circuit can be removed. Therefore, the circuit simplification and power consumption of the inverter device are improved, thereby improving efficiency.

Korean Open Patent No. 10-2015-0121988 (2015.10.30) Korean Open Patent No. 10-2011-0078962 (2011.07.07)

One embodiment of the present invention is to provide a SiC inverter device having a structure that can maximize the performance of the SiC inverter to speed up the switching speed and minimize the switching loss.

One embodiment of the present invention is to provide a SiC inverter device having a structure capable of minimizing the parasitic inductance generated between the SiC switching module and the DC link capacitor.

One embodiment of the present invention is to provide a SiC inverter device having a structure capable of reducing a spike voltage including a snubber circuit and simultaneously minimizing parasitic inductance of the snubber circuit itself.

Among the embodiments, the SiC inverter device includes a SiC switching module, a DC link capacitor disposed on the SiC switching module, a gate driver disposed on the side of the SiC switching module, and a direct connection between the SiC switching module and the DC link capacitor. It includes a DC link bus bar and a fixing bracket for fixing the gate driver to the side of the SiC switching module.

The DC link busbar includes a first fastening part coupled to an upper surface of the SiC switching module through a first fastening member, a second fastening part connected to a lower surface of the DC link capacitor through a second fastening member, and the first fastening It may be configured as a connecting portion connecting the second fastening portion and the SiC switching module and the DC link capacitor spaced below a predetermined interval.

The fixing bracket may separate the gate driver from the SiC switching module to a predetermined interval or less.

In embodiments, the SiC inverter device may further include a snubber circuit for reducing a spike voltage caused by parasitic inductance between the SiC switching module and the DC link capacitor.

The snubber circuit is disposed between the SiC switching module and the first fastening portion of the DC link busbar, and can be coupled together through the SiC switching module and the DC link busbar and the first fastening member.

The DC link busbar is composed of positive and negative DC link busbars respectively connected to positive and negative terminals of the DC link capacitor, and the snubber circuit is disposed between the positive DC link busbar and the negative DC link busbar. Can be.

The disclosed technology can have the following effects. However, since the specific embodiment does not mean that all of the following effects should be included or only the following effects are included, the scope of rights of the disclosed technology should not be understood as being limited thereby.

The SiC inverter device according to an embodiment of the present invention may have a structure capable of maximizing the performance of a SiC inverter that speeds up switching speed and minimizes switching loss.

SiC inverter device according to an embodiment of the present invention may be formed of a structure that can minimize the parasitic inductance generated between the SiC switching module and the DC link capacitor.

SiC inverter device according to an embodiment of the present invention can be formed of a structure that can reduce the spike voltage, including a snubber circuit, and at the same time minimize the parasitic inductance of the snubber circuit itself.

1 is a view showing a SiC inverter device according to an embodiment of the present invention.
FIG. 2 is a view showing a DC link bus bar in FIG. 1.
3 is a view showing the structure of the gate driver and the fixing bracket in FIG.
4 is a view showing a coupling structure of a snubber circuit according to an embodiment of the present invention.
5 is a diagram illustrating a DC input unit configuration of a SiC inverter device according to an embodiment.

Since the description of the present invention is merely an example for structural or functional description, the scope of the present invention should not be interpreted as being limited by the examples described in the text. That is, since the embodiments can be variously modified and have various forms, it should be understood that the scope of the present invention includes equivalents capable of realizing technical ideas. In addition, the object or effect presented in the present invention does not mean that a specific embodiment should include all of them or only such an effect, and the scope of the present invention should not be understood as being limited thereby.

Meanwhile, the meaning of terms described in the present application should be understood as follows.

Terms such as "first" and "second" are for distinguishing one component from other components, and the scope of rights should not be limited by these terms. For example, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.

When a component is said to be "connected" to another component, it may be understood that other components may exist in the middle, although they may be directly connected to the other component. On the other hand, when a component is said to be "directly connected" to another component, it should be understood that no other component exists in the middle. On the other hand, other expressions describing the relationship between the components, that is, "between" and "immediately between" or "neighboring to" and "directly neighboring to" should be interpreted similarly.

Singular expressions are to be understood as including plural expressions unless the context clearly indicates otherwise, and terms such as “comprises” or “have” are used features, numbers, steps, actions, components, parts or the like. It is to be understood that a combination is intended to be present, and should not be understood as pre-excluding the existence or addition possibility of one or more other features or numbers, steps, actions, components, parts or combinations thereof.

In each step, the identification code (for example, a, b, c, etc.) is used for convenience of explanation. The identification code does not describe the order of each step, and each step clearly identifies a specific order in context. Unless stated, it may occur in a different order than specified. That is, each step may occur in the same order as specified, may be performed substantially simultaneously, or may be performed in the reverse order.

The present invention can be embodied as computer readable code on a computer readable recording medium, and the computer readable recording medium includes all kinds of recording devices in which data readable by a computer system is stored. . Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disks, and optical data storage devices. In addition, the computer-readable recording medium can be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

All terms used herein have the same meaning as generally understood by a person skilled in the art to which the present invention pertains, unless otherwise defined. The terms defined in the commonly used dictionary should be interpreted as being consistent with the meanings in the context of the related art, and cannot be interpreted as having ideal or excessively formal meanings unless explicitly defined in the present application.

1 is a view showing a SiC inverter device according to an embodiment of the present invention.

Referring to FIG. 1, the SiC inverter device 100 includes a SiC switching module 10, a DC link capacitor 20, a gate driver 30, a DC link bus bar 110, and a fixed bracket 120.

The SiC (Silicon Carbide) inverter device 100 corresponds to an inverter using a SiC switching module 10, and is compared to an inverter using an Si (Silicon, silicon) power device (IGBT, Insulated Gate Bipolar Transistor) Less power loss and faster switching speed. More specifically, the SiC inverter device 100 may have advantages of high-speed switching of 20 kHz or higher, low switching loss due to a fast switching state transition time, and low noise due to switching over audible frequencies.

The SiC switching module 10 has advantages such as fast switching and low power loss due to switching, as mentioned. For example, the SiC switching module 10 may be composed of a SiC-MOSFET. However, the SiC switching module 10 generates a large spike voltage due to a parasitic inductance component parasitic between the switching module 10 and the DC link capacitor 20 due to the fast switching transition time, and accordingly, electromagnetic interference in the 30 MHz band (EMI) It can cause noise. The electromagnetic interference noise component may be conductive or radioactive and may cause malfunction of peripheral devices. The electromagnetic interference noise component can be solved by applying an electromagnetic interference (EMI) filter and shield, but the spike voltage can be solved by using a snubber circuit to minimize loss or by changing the structure of the SiC inverter. The present invention discloses a SiC inverter device 100 having a structure for solving the above problems of parasitic inductance and spike voltage.

The DC link capacitor 20 serves to maintain the voltage so that a constant voltage can be supplied during power conversion in the SiC inverter device 100. In one embodiment, the DC link capacitor 20 may be disposed on top of the SiC switching module 10.

The gate driver 30 may be disposed on the side of the switching module 10. Here, the gate driver 30 may correspond to a power amplifier that receives a low power input and generates a high current drive input to a gate of a high power transistor such as the SiC switching module 10.

The DC link bus bar 110 may directly connect the SiC switching module 10 and the DC link capacitor 20. More specifically, the DC link busbar 110 may minimize the distance between the SiC switching module 10 and the DC link capacitor 20 by placing the DC link capacitor 20 on top of the SiC switching module 10. .

The fixing bracket 120 can fix the gate driver 30 to the side of the SiC switching module 10. More specifically, the fixed bracket 120 can minimize the parasitic inductance by placing the gate driver 30 as close as possible to the side of the switching module 10.

FIG. 2 is a view showing a DC link bus bar in FIG. 1.

The DC link bus bar 110 may be composed of a positive DC link bus bar 110b connected to the positive terminal of the DC link capacitor 20 and a negative DC link bus bar 110a connected to the negative terminal of the DC link capacitor 20. have.

In one embodiment, the DC link busbar 110 may include a first fastening portion 112 coupled to the top surface of the SiC switching module 10 through a first fastening member. Here, the bus bar (bus bar) may mean a rod-type conductor that enables electrical connection in a tram, vehicle, aircraft, or the like. The DC link bus bar 110 may correspond to a rod-shaped conductor that electrically connects the DC link capacitor 20 to the SiC switching module 10. In one embodiment, the first fastening part 112 may be implemented in the form of a fastening hole through which the first fastening member in the form of a screw can penetrate. For example, the DC link bus bar 110 is a DC link bus bar on the top surface of the SiC switching module 10 through a first fastening member that is fixed to the SiC switching module 10 through the first fastening part 112. One side of 110 may be combined.

In one embodiment, the DC link bus bar 110 may include a second fastening portion 114 connected to the lower surface of the DC link capacitor 20 through the second fastening member. In one embodiment, the second fastening portion 114, like the first fastening portion 112, may be implemented in the form of a fastening hole through the second fastening member in the form of a screw. More specifically, the DC link bus bar 110 penetrates the second fastening portion 114 and the DC link bus bar on the lower surface of the DC link capacitor 20 through a second fastening member fixed to the DC link capacitor 20. The opposite side of (110) can be fixed.

In one embodiment, the DC link bus bar 110 may include a connecting portion 116 connecting the first fastening portion 112 and the second fastening portion 114. More specifically, the DC link bus bar 110 is formed in a bar shape, and the first fastening part 112 formed parallel to the plane of the SiC switching module, and the connecting part that is bent vertically along the curved surface from the first fastening part ( 116) and a second fastening portion 114 formed in parallel to the plane of the DC link capacitor 20 by being vertically bent toward the opposite direction to the first fastening portion 112 along the curved surface again at the connection portion 116 Can be. For example, the DC link bus bar 110 may be implemented in the form of a lying chair. More specifically, the DC link bus bar 110 may arrange the DC link capacitor 20 to be spaced a predetermined distance on top of the SiC switching module 10.

In one embodiment, the DC link busbar 110 may space the SiC switching module 10 and the DC link capacitor 20 below a predetermined interval. More specifically, the DC link bus bar 110 is spaced apart from the DC link capacitor 20 and the SiC switching module 10 to avoid interference due to contact, and to minimize switching power loss due to parasitic inductance caused by separation. For this, the separation distance can be determined to be below a certain distance. For example, the DC link bus bar 110 may minimize parasitic inductance by minimizing the length of the connection portion 116. More specifically, the DC link bus bar 110 may be formed to have a gap between the SiC switching module 10 and the DC link capacitor 20 shorter than a predetermined interval that mainly generates parasitic inductance. In one embodiment, the DC link bus bar 110 may vary the length of the connection 116 according to the size of the parasitic inductance generated between the SiC switching module 10 and the DC link capacitor 20. For example, the DC link bus bar 110 may form the connection portion 116 in a length-adjustable form, and parasitic inductance generated between the SiC switching module 10 and the DC link capacitor 20 as necessary. In order to minimize the length of the connection portion 116 can be adjusted. In one embodiment, the DC link busbar 110 may detect the size of the parasitic inductance through its own sensor and adjust the length of the connection portion 116 to a length that minimizes the size of the detected parasitic inductance. More specifically, the DC link bus bar 110 may minimize the parasitic inductance by forming a gap between the SiC switching module 110 and the DC link capacitor at a predetermined interval or less through the length of the connection portion 116.

3 is a view showing the structure of the gate driver and the fixing bracket in FIG.

The gate driver 30 may serve to control on / off of the SiC switching module 10. When the distance between the gate driver 30 and the SiC switching module 10 is more than a certain distance, parasitic inductance components are generated as in the relationship with the DC link capacitor 20, so that the on / off of the SiC switching module 10 is not accurately maintained. It can be prevented. Accordingly, the SiC inverter device 100 may include a fixing bracket 120 to place the gate driver 30 as close as possible to the SiC switching module 10. In one embodiment, the fixed bracket 120 may separate the gate driver 30 from the SiC switching module 10 at a predetermined interval or less. More specifically, the fixing bracket 120 may fix the gate driver 30 to be spaced apart at a predetermined interval or less on the side surface of the SiC switching module 10. In one embodiment, the fixed bracket 120 secures the gate driver 30 as close as possible to the proximal side of the SiC switching module 10 to minimize parasitic inductance between the SiC switching module 10 and the gate driver 30. Can be. More specifically, the fixed bracket 120 is a gate driver 30 and the SiC switching module 10 in order to minimize the parasitic inductance that occurs according to the predetermined distance between the gate driver 30 and the SiC switching module 10 It can be spaced below a certain interval. That is, the fixed bracket 120 may arrange the gate driver 30 to be spaced at a minimum distance from the SiC switching module 10.

In one embodiment, the predetermined interval can be obtained from the following equation.

[Mathematics]

Here, g may correspond to a constant interval, k to a proportional constant, A to a parasitic inductance value, and B to a spike voltage value.

4 is a view showing a coupling structure of a snubber circuit according to an embodiment of the present invention.

In FIG. 4, the SiC inverter device 100 may further include a snubber circuit 130 to reduce the spike voltage caused by parasitic inductance between the SiC switching module 10 and the DC link capacitor 20. . Here, the snubber circuit 130 may correspond to a buffer circuit used to soften abrupt changes occurring when the power is turned on / off and remove unwanted noise and the like from the input signal. The snubber circuit 130 can reduce the spike voltage to prevent burnout of the SiC inverter device 100, but may increase the switching loss by the parasitic inductance component or resistance component of the snubber circuit itself. Therefore, the SiC inverter device 100 can minimize the parasitic inductance component by arranging the snubber circuit 130 to be directly attached to the upper surface of the SiC switching module 10.

In one embodiment, the snubber circuit 130 may be disposed between the SiC switching module 10 and the first fastening portion 112 of the DC link bus bar 110. For example, the snubber circuit 130 is placed directly on the top surface of the SiC switching module 10 and disposed at the shortest distance from the SiC switching module 10, and the DC link bus bar 110 can be fixed thereon. More specifically, the snubber circuit 130 is disposed between the SiC switching module 10 and the DC link busbar 110, and the SiC switching is performed through the first fastening portion 112 and the snubber circuit 130. The SiC switching module 10 and the DC link bus bar 110 may be coupled through a first fastening member fixed to the module 10.

In one embodiment, snubber circuit 130 may be disposed between a positive DC link busbar and a negative DC link busbar. More specifically, the snubber circuit 130 can be directly coupled with the SiC switching module 10 in the shortest distance in order to minimize the loss generated by itself, and for this purpose, the SiC switching module 10 and the DC link capacitor 20 ) Can be placed between plus and minus DC link busbars that combine the shortest distances. In one embodiment, the snubber circuit 130 may use a capacitor having very low equivalent series resistance (ESR) and equivalent series inductance (ESL). The snubber circuit 130 is disposed at the shortest distance between the SiC switching module 10 and the DC link capacitor 20 to reduce the loss occurring in the snubber circuit 130 itself, minimize parasitic inductance components, and spike voltage It is possible to prevent burnout of the device.

5 is a view showing a DC input unit configuration of a SiC inverter device according to an embodiment.

In one embodiment, the SiC inverter device 100 may include a DC input unit 40. More specifically, the SiC inverter device 100 may be connected to another device or system through the DC input unit 40 protruding from the SiC switching module 10 to the outside of the SiC inverter device 100. For example, the DC input unit 40 may be used when connected to a system that outputs DC power, such as a battery management system or an energy storage device, and may be combined in a module form with a converter system that converts AC power into DC power. have.

Although described above with reference to preferred embodiments of the present invention, those skilled in the art variously modify and change the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. You can understand that you can.

10: SiC switching module
20: DC link capacitor
30: gate driver
40: DC input
100: SiC inverter device
110: DC link bus bar 112: first connection
114: second fastening portion 116: connecting portion
120: fixed bracket
130: snubber circuit

Claims (6)

SiC switching module;
A DC link capacitor disposed on the SiC switching module;
A gate driver disposed on a side of the SiC switching module;
A DC link bus bar directly connecting the SiC switching module and the DC link capacitor;
A fixing bracket for fixing the gate driver to the side of the SiC switching module; And
It includes a snubber circuit for reducing the spike voltage due to the parasitic inductance generated between the SiC switching module and the DC link capacitor,
The fixed bracket spaces the gate driver at a predetermined interval or less from the side of the SiC switching module,
The DC link busbar is implemented as a modular connecting member having both ends connected to each of the fastening parts, so that the positive and negative ends of the DC link capacitor are independently connected to each other. Forming positive and negative DC link busbars being deployed,
The snubber circuit is characterized by being arranged in a space between the plus and minus DC link busbars as a result of being supported and combined by a square board disposed between the upper surface of the SiC switching module and the fastening unit. SiC inverter device.
According to claim 1, The DC link bus bar
A first fastening part coupled to an upper surface of the SiC switching module through a first fastening member, a second fastening part connected to a lower surface of the DC link capacitor through a second fastening member, and the first fastening part and the second fastening part SiC inverter device characterized in that it comprises a connecting portion for connecting and spaced apart the predetermined distance or less between the SiC switching module and the DC link capacitor.
delete delete The snubber circuit according to claim 2, wherein
SiC switching device is arranged between the SiC switching module and the first fastening portion of the DC link busbar, the SiC switching module and the DC link busbar and the SiC inverter device, characterized in that coupled together through the first fastening member.
delete

Images