Bonding-wire-free double-sided heat dissipation SiC-MOSFET bare chip inverter structure based on copper substrate

Abstract

The invention discloses a bonding-wire-free double-sided heat dissipation SiC-MOSFET bare chip inverter structure based on a copper substrate, which comprises a positive direct-current conductive copper bar, a first copper bar, a second copper bar and a negative direct-current bus copper bar, and is characterized in that the positive direct-current conductive copper bar is connected with the drain electrode D of an upper bridge arm switch tube Q1 and the drain electrode D of an upper bridge arm switch tube Q2; the first copper bar is connected with the drain electrode of the lower bridge arm switch tube Q3 and the source electrode of the upper bridge arm switch tube Q1; the second copper bar is connected with the drain electrode of the lower bridge arm switch tube Q4 and the source electrode of the bridge arm switch tube Q2. The negative direct current bus copper bar is connected with the source electrode of the lower bridge arm switch tube Q3 and the source electrode of the lower bridge arm switch tube Q4. The SiC-MOSFET bare chip converter solves the problems that in the prior art, due to the fact that an SiC-MOSFET bare chip converter adopts a single-face heat dissipation and bonding wire connection mode, reliability is low, and parasitic inductance is large.

Description

Technical Field

[0001] The invention belongs to the technical field of power converters and relates to a SiC-MOSFET bare chip inverter structure with no bonding wires and double-sided heat dissipation based on a copper substrate. Background Art

[0002] The third generation wide bandgap semiconductor device SiC-MOSFET has significantly improved the inverter power density and transmission efficiency based on its excellent switching, conduction, heat resistance and high degree of localization. However, the mainstream packaging technology of SiC-MOSFET still uses aluminum wire bonding packaging, which is relatively backward in development, has low current stress, and the market-oriented TO-247 package is large in size and has large pin parasitic parameters, which limits the switching frequency of SiC-MOSFET in actual work. At the same time, since the switching devices using bonding wire packaging technology use a single-sided heat dissipation method, the thermal resistance of the commonly used TO-247 packaged SiC-MOSFET devices is large, and the power loop area and heat dissipation system of the inverter based on SiC-MOSFET are large, which also seriously hinders the optimization of inverter power density and transmission efficiency.

[0003] Therefore, it is necessary to carry out research on the application of new packaging technology for SiC-MOSFET, reduce the parasitic parameters and thermal resistance of the circuit, and maximize the high frequency, low loss and high heat resistance characteristics of SiC-MOSFET. In order to achieve the above goals, the use of SiC-MOSFET bare chips to build power converters has become a new research direction. However, due to the staggered connection of electrodes in the converter (all upper arm switch tubes are connected to the drain, and all lower arm switch tubes are connected to the source) and the distribution characteristics of the two sides of the SiC-MOSFET bare chip electrodes (the gate and source are located on the front, and the drain is located on the back), the system structure design is relatively complex. At present, the converter design based on SiC-MOSFET bare chips still mainly adopts aluminum substrates and single-sided heat dissipation. Compared with independent devices in TO-247 packaging, the single-sided heat dissipation structure based on bare chips effectively reduces the thermal resistance of the device and enhances the heat dissipation capacity, but the gate and source are still connected to the driver pins by bonding wires. The reliability is low in practical applications, and the parasitic inductance in the power and drive circuits cannot be effectively reduced, which limits the high frequency and miniaturization of the converter. Summary of the invention

[0004] The purpose of the present invention is to provide a SiC-MOSFET bare chip inverter structure with no bonding wires and double-sided heat dissipation based on a copper substrate, so as to solve the problems in the prior art that the SiC-MOSFET bare chip converter adopts single-sided heat dissipation and bonding wire connection, resulting in low reliability and large parasitic inductance.

[0005] The technical solution adopted by the present invention is a SiC-MOSFET bare chip inverter structure with no bonding wire and double-sided heat dissipation based on a copper substrate, including a copper substrate, and an upper bridge arm switch tube Q1, an upper bridge arm switch tube Q2, a lower bridge arm switch tube Q3 and a lower bridge arm switch tube Q4 connected to the copper substrate, and also includes a positive DC conductive copper bar, a first copper bar, a second copper bar and a negative DC bus copper bar, the positive DC conductive copper bar is connected to the drain D of the upper bridge arm switch tube Q1 and the upper bridge arm switch tube Q2; the first copper bar is connected to the drain of the lower bridge arm switch tube Q3 and the source of the upper bridge arm switch tube Q1; the second copper bar is connected to the drain of the lower bridge arm switch tube Q4 and the source of the bridge arm switch tube Q2, and the negative DC bus copper bar is connected to the source of the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4.

[0006] The present invention is also characterized in that:

[0007] The copper substrate includes a copper bottom layer and an insulating layer on the copper bottom layer. The gate electrodes G of the upper arm switch tube Q1, the upper arm switch tube Q2, the lower arm switch tube Q3 and the lower arm switch tube Q4 are insulated from the copper bottom layer of the copper substrate. The pins of the electrical components in the upper arm switch tube Q1, the upper arm switch tube Q2, the lower arm switch tube Q3 and the lower arm switch tube Q4 are connected by single-layer PCB wiring. The source electrodes S of the upper arm switch tube Q1, the upper arm switch tube Q2, the lower arm switch tube Q3 and the lower arm switch tube Q4 are directly connected to the copper bottom layer of the copper substrate after being subjected to electric and thermal separation treatment.

[0008] The upper arm switch tube Q1, the upper arm switch tube Q2, the lower arm switch tube Q3 and the lower arm switch tube Q4 are respectively connected to their corresponding gate drive circuits, and the gate drive circuits of the upper arm switch tube Q1, the upper arm switch tube Q2, the lower arm switch tube Q3 and the lower arm switch tube Q4 are all insulated from the copper bottom layer of the copper substrate, and the pins of each electrical component in the four gate drive circuits are connected by single-layer PCB wiring.

[0009] The positive DC conductive copper bus is designed as a heat sink structure.

[0010] The upper-arm switch tube Q1 and the upper-arm switch tube Q2 are both formed by two SiC-MOSFET bare chips connected in parallel.

[0011] The first copper bar and the second copper bar are arranged side by side, and the first copper bar is connected to the drain of the lower bridge arm switch tube Q3 and the source of the upper bridge arm switch tube Q1 as a high-frequency AC output terminal;

[0012] The second copper bus serves as another high-frequency AC output terminal and is connected to the drain of the lower bridge arm switch tube Q4 and the source of the bridge arm switch tube Q2.

[0013] The first copper bar and the second copper bar have the same structure, and are both configured as heat sink structures.

[0014] The lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are both formed by two SiC-MOSFET bare chips connected in parallel.

[0015] The structure of the negative DC bus copper bar is the same as that of the positive DC conductive copper bar, both of which are heat sink structures, and the negative DC bus copper bar and the positive DC conductive copper bar are arranged correspondingly.

[0016] The beneficial effects of the present invention are:

[0017] (1) In the present invention, four conductive copper bars are simultaneously connected to the drain D and source S of the SiC-MOSFET bare chip, providing a power loop for DC current and AC output, while realizing a double-sided heat dissipation method, and the thermal resistance of the inverter is low.

[0018] (2) The SiC-MOSFET bare chip of the present invention adopts a non-bonding wire method on the copper substrate, and the gate driver output terminal is directly connected to the gate (G) and source (S) of the device, which shortens the wire length and reduces the parasitic inductance value of the drive loop. At the same time, all devices are welded to the copper substrate on a plane, thereby increasing the system reliability.

[0019] (3) The DC and AC conductive copper busbars of the present invention adopt a heat sink structure, and each switching device has a similar electrical and thermal circuit, which can reduce the thermal imbalance problem caused by the asymmetry of electrical and thermal parameters. It is easy to achieve thermal balance for parallel devices, and there will be no overheating failure problem due to different device temperatures. The system reliability is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a SiC-MOSFET bare chip inverter structure with no bonding wires and double-sided heat dissipation based on a copper substrate of the present invention;

[0021] Figure 2 It is a circuit connection diagram of a SiC-MOSFET bare chip inverter structure with no bonding wire and double-sided heat dissipation based on a copper substrate of the present invention;

[0022] Figure 3 It is a schematic diagram of the connection method between a single SiC-MOSFET bare chip and its gate drive circuit and a copper substrate in the present invention.

[0023] In the figure: 1. Positive DC conductive copper busbar, 2. Copper base plate, 3. Insulation layer, 4. First copper busbar, 5. Second copper busbar, 6. Copper base layer, 7. Negative DC conductive copper busbar. DETAILED DESCRIPTION

[0024] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Example 1

[0026] The present invention is based on a copper substrate without bonding wires and a double-sided heat dissipation SiC-MOSFET bare chip inverter structure, and its structure is as follows Figure 1-3 As shown, it includes a copper substrate 2, and an upper bridge arm switch tube Q1, an upper bridge arm switch tube Q2, a lower bridge arm switch tube Q3 and a lower bridge arm switch tube Q4 connected to the copper substrate 2, and also includes a positive DC conductive copper bar 1, a first copper bar 4, a second copper bar 5 and a negative DC bus copper bar 7. The positive DC conductive copper bar 1 is connected to the drain D of the upper bridge arm switch tube Q1 and the upper bridge arm switch tube Q2; the first copper bar 4 is connected to the drain of the lower bridge arm switch tube Q3 and the source of the upper bridge arm switch tube Q1; the second copper bar 5 is connected to the drain of the lower bridge arm switch tube Q4 and the source of the bridge arm switch tube Q2, and the negative DC bus copper bar 7 is connected to the source of the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4.

[0027] Example 2

[0028] The present invention is based on a copper substrate without bonding wires and a double-sided heat dissipation SiC-MOSFET bare chip inverter structure, and its structure is as follows Figure 1-3 As shown, it includes a copper substrate 2, and an upper bridge arm switch tube Q1, an upper bridge arm switch tube Q2, a lower bridge arm switch tube Q3 and a lower bridge arm switch tube Q4 connected to the copper substrate 2, and also includes a positive DC conductive copper bar 1, a first copper bar 4, a second copper bar 5 and a negative DC bus copper bar 7. The positive DC conductive copper bar 1 is connected to the drain D of the upper bridge arm switch tube Q1 and the upper bridge arm switch tube Q2; the first copper bar 4 is connected to the drain of the lower bridge arm switch tube Q3 and the source of the upper bridge arm switch tube Q1; the second copper bar 5 is connected to the drain of the lower bridge arm switch tube Q4 and the source of the bridge arm switch tube Q2, and the negative DC bus copper bar 7 is connected to the source of the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4.

[0029] The copper substrate includes a copper bottom layer and an insulating layer 3 on the copper bottom layer 6. The gates G of the upper bridge arm switch tube Q1, the upper bridge arm switch tube Q2, the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are insulated from the copper bottom layer of the copper substrate. The pins of each electrical component in the upper bridge arm switch tube Q1, the upper bridge arm switch tube Q2, the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are connected by single-layer board PCB wiring. The source S of the upper bridge arm switch tube Q1, the upper bridge arm switch tube Q2, the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are directly connected to the copper bottom layer 6 of the copper substrate after being electrically and thermally separated.

[0030] Example 3

[0031] The present invention is based on a copper substrate without bonding wires and a double-sided heat dissipation SiC-MOSFET bare chip inverter structure, and its structure is as follows Figure 1-3As shown, it includes a copper substrate 2, and an upper bridge arm switch tube Q1, an upper bridge arm switch tube Q2, a lower bridge arm switch tube Q3 and a lower bridge arm switch tube Q4 connected to the copper substrate 2, and also includes a positive DC conductive copper bar 1, a first copper bar 4, a second copper bar 5 and a negative DC bus copper bar 7. The positive DC conductive copper bar 1 is connected to the drain D of the upper bridge arm switch tube Q1 and the upper bridge arm switch tube Q2; the first copper bar 4 is connected to the drain of the lower bridge arm switch tube Q3 and the source of the upper bridge arm switch tube Q1; the second copper bar 5 is connected to the drain of the lower bridge arm switch tube Q4 and the source of the bridge arm switch tube Q2, and the negative DC bus copper bar 7 is connected to the source of the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4.

[0032] The copper substrate includes a copper bottom layer and an insulating layer 3 on the copper bottom layer 6. The gates G of the upper bridge arm switch tube Q1, the upper bridge arm switch tube Q2, the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are insulated from the copper bottom layer of the copper substrate. The pins of each electrical component in the upper bridge arm switch tube Q1, the upper bridge arm switch tube Q2, the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are connected by single-layer board PCB wiring. The source S of the upper bridge arm switch tube Q1, the upper bridge arm switch tube Q2, the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are directly connected to the copper bottom layer 6 of the copper substrate after being electrically and thermally separated.

[0033] The upper arm switch tube Q1, the upper arm switch tube Q2, the lower arm switch tube Q3 and the lower arm switch tube Q4 are respectively connected to their corresponding gate drive circuits, and the gate drive circuits of the upper arm switch tube Q1, the upper arm switch tube Q2, the lower arm switch tube Q3 and the lower arm switch tube Q4 are all insulated from the copper bottom layer of the copper substrate, and the pins of each electrical component in the four gate drive circuits are connected by single-layer PCB wiring.

[0034] The upper-arm switch tube Q1 and the upper-arm switch tube Q2 are both formed by two SiC-MOSFET bare chips connected in parallel.

[0035] Example 4

[0036] The present invention is based on a copper substrate without bonding wires and a double-sided heat dissipation SiC-MOSFET bare chip inverter structure, and its structure is as follows Figure 1-3As shown, it includes a copper substrate 2, and an upper bridge arm switch tube Q1, an upper bridge arm switch tube Q2, a lower bridge arm switch tube Q3 and a lower bridge arm switch tube Q4 connected to the copper substrate 2, and also includes a positive DC conductive copper bar 1, a first copper bar 4, a second copper bar 5 and a negative DC bus copper bar 7. The positive DC conductive copper bar 1 is connected to the drain D of the upper bridge arm switch tube Q1 and the upper bridge arm switch tube Q2; the first copper bar 4 is connected to the drain of the lower bridge arm switch tube Q3 and the source of the upper bridge arm switch tube Q1; the second copper bar 5 is connected to the drain of the lower bridge arm switch tube Q4 and the source of the bridge arm switch tube Q2, and the negative DC bus copper bar 7 is connected to the source of the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4.

[0037] The copper substrate includes a copper bottom layer and an insulating layer 3 on the copper bottom layer 6. The gates G of the upper bridge arm switch tube Q1, the upper bridge arm switch tube Q2, the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are insulated from the copper bottom layer of the copper substrate. The pins of each electrical component in the upper bridge arm switch tube Q1, the upper bridge arm switch tube Q2, the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are connected by single-layer board PCB wiring. The source S of the upper bridge arm switch tube Q1, the upper bridge arm switch tube Q2, the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are directly connected to the copper bottom layer 6 of the copper substrate after being electrically and thermally separated.

[0038] The upper arm switch tube Q1, the upper arm switch tube Q2, the lower arm switch tube Q3 and the lower arm switch tube Q4 are respectively connected to their corresponding gate drive circuits, and the gate drive circuits of the upper arm switch tube Q1, the upper arm switch tube Q2, the lower arm switch tube Q3 and the lower arm switch tube Q4 are all insulated from the copper bottom layer of the copper substrate, and the pins of each electrical component in the four gate drive circuits are connected by single-layer PCB wiring.

[0039] The upper-arm switch tube Q1 and the upper-arm switch tube Q2 are both formed by two SiC-MOSFET bare chips connected in parallel.

[0040] The positive DC conductive copper busbar 1 is designed as a radiator structure, that is, a commonly used shutter structure. The positive DC conductive copper busbar 1 realizes conduction and also serves as a heat dissipation module for the upper arm switch tube Q1 and the upper arm switch tube Q2. It is used for heat dissipation of the upper arm switch tube Q1 and the upper arm switch tube Q2, realizing a structure that combines conduction and heat dissipation, and improving heat dissipation performance.

[0041] Example 5

[0042] The present invention is based on a copper substrate without bonding wires and a double-sided heat dissipation SiC-MOSFET bare chip inverter structure, and its structure is as follows Figure 1-3As shown, it includes a copper substrate 2, and an upper bridge arm switch tube Q1, an upper bridge arm switch tube Q2, a lower bridge arm switch tube Q3 and a lower bridge arm switch tube Q4 connected to the copper substrate 2, and also includes a positive DC conductive copper bar 1, a first copper bar 4, a second copper bar 5 and a negative DC bus copper bar 7. The positive DC conductive copper bar 1 is connected to the drain D of the upper bridge arm switch tube Q1 and the upper bridge arm switch tube Q2; the first copper bar 4 is connected to the drain of the lower bridge arm switch tube Q3 and the source of the upper bridge arm switch tube Q1; the second copper bar 5 is connected to the drain of the lower bridge arm switch tube Q4 and the source of the bridge arm switch tube Q2, and the negative DC bus copper bar 7 is connected to the source of the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4.

[0043] The copper substrate includes a copper bottom layer and an insulating layer 3 on the copper bottom layer 6. The gates G of the upper bridge arm switch tube Q1, the upper bridge arm switch tube Q2, the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are insulated from the copper bottom layer of the copper substrate. The pins of each electrical component in the upper bridge arm switch tube Q1, the upper bridge arm switch tube Q2, the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are connected by single-layer board PCB wiring. The source S of the upper bridge arm switch tube Q1, the upper bridge arm switch tube Q2, the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are directly connected to the copper bottom layer 6 of the copper substrate after being electrically and thermally separated.

[0044] The upper arm switch tube Q1, the upper arm switch tube Q2, the lower arm switch tube Q3 and the lower arm switch tube Q4 are respectively connected to their corresponding gate drive circuits, and the gate drive circuits of the upper arm switch tube Q1, the upper arm switch tube Q2, the lower arm switch tube Q3 and the lower arm switch tube Q4 are all insulated from the copper bottom layer of the copper substrate, and the pins of each electrical component in the four gate drive circuits are connected by single-layer PCB wiring.

[0045] The upper-arm switch tube Q1 and the upper-arm switch tube Q2 are both formed by two SiC-MOSFET bare chips connected in parallel.

[0046] The positive DC conductive copper busbar 1 is designed as a heat sink structure in the shape of a common shutter. The positive DC conductive copper busbar 1 realizes conduction and also serves as a heat dissipation module for the upper arm switch tube Q1 and the upper arm switch tube Q2. It is used for heat dissipation of the upper arm switch tube Q1 and the upper arm switch tube Q2, realizing a structure that shares conduction and heat dissipation, and improving heat dissipation performance.

[0047] The first copper bar 4 and the second copper bar 5 are arranged side by side, and the first copper bar 4 is connected to the drain of the lower bridge arm switch tube Q3 and the source of the upper bridge arm switch tube Q1 as a high-frequency AC output terminal;

[0048] The second copper bus 5 serves as another high-frequency AC output terminal, and is connected to the drain of the lower bridge arm switch tube Q4 and the source of the bridge arm switch tube Q2.

[0049] The first copper bar 4 and the second copper bar 5 have the same structure and are both configured as heat sink structures; the first copper bar 4 serves as an AC conductive copper bar, which realizes conduction and dissipates heat for the drain of the lower arm switch tube Q3 and the upper arm switch tube Q1; the second copper bar 5 realizes conduction and dissipates heat for the drain of the lower arm switch tube Q4 and the bridge arm switch tube Q2.

[0050] The lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are both formed by two SiC-MOSFET bare chips connected in parallel.

[0051] Example 6

[0052] The present invention is based on a copper substrate without bonding wires and a double-sided heat dissipation SiC-MOSFET bare chip inverter structure, and its structure is as follows Figure 1-3 As shown, it includes a copper substrate 2, and an upper bridge arm switch tube Q1, an upper bridge arm switch tube Q2, a lower bridge arm switch tube Q3 and a lower bridge arm switch tube Q4 connected to the copper substrate 2, and also includes a positive DC conductive copper bar 1, a first copper bar 4, a second copper bar 5 and a negative DC bus copper bar 7. The positive DC conductive copper bar 1 is connected to the drain D of the upper bridge arm switch tube Q1 and the upper bridge arm switch tube Q2; the first copper bar 4 is connected to the drain of the lower bridge arm switch tube Q3 and the source of the upper bridge arm switch tube Q1; the second copper bar 5 is connected to the drain of the lower bridge arm switch tube Q4 and the source of the bridge arm switch tube Q2, and the negative DC bus copper bar 7 is connected to the source of the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4.

[0053] The copper substrate includes a copper bottom layer and an insulating layer 3 on the copper bottom layer 6. The gates G of the upper bridge arm switch tube Q1, the upper bridge arm switch tube Q2, the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are insulated from the copper bottom layer of the copper substrate. The pins of each electrical component in the upper bridge arm switch tube Q1, the upper bridge arm switch tube Q2, the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are connected by single-layer board PCB wiring. The source S of the upper bridge arm switch tube Q1, the upper bridge arm switch tube Q2, the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are directly connected to the copper bottom layer 6 of the copper substrate after being electrically and thermally separated.

[0054] The upper arm switch tube Q1, the upper arm switch tube Q2, the lower arm switch tube Q3 and the lower arm switch tube Q4 are respectively connected to their corresponding gate drive circuits, and the gate drive circuits of the upper arm switch tube Q1, the upper arm switch tube Q2, the lower arm switch tube Q3 and the lower arm switch tube Q4 are all insulated from the copper bottom layer of the copper substrate, and the pins of each electrical component in the four gate drive circuits are connected by single-layer PCB wiring.

[0055] The upper-arm switch tube Q1 and the upper-arm switch tube Q2 are both formed by two SiC-MOSFET bare chips connected in parallel.

[0056] The positive DC conductive copper busbar 1 is designed as a heat sink structure in the shape of a common shutter. The positive DC conductive copper busbar 1 realizes conduction and also serves as a heat dissipation module for the upper arm switch tube Q1 and the upper arm switch tube Q2. It is used for heat dissipation of the upper arm switch tube Q1 and the upper arm switch tube Q2, realizing a structure that shares conduction and heat dissipation, and improving heat dissipation performance.

[0057] The first copper bar 4 and the second copper bar 5 are arranged side by side, and the first copper bar 4 is connected to the drain of the lower bridge arm switch tube Q3 and the source of the upper bridge arm switch tube Q1 as a high-frequency AC output terminal;

[0058] The second copper bus 5 serves as another high-frequency AC output terminal, and is connected to the drain of the lower bridge arm switch tube Q4 and the source of the bridge arm switch tube Q2.

[0059] The first copper bar 4 and the second copper bar 5 have the same structure and are both configured as a radiator structure, that is, a commonly used shutter structure. The first copper bar 4 serves as an AC conductive copper bar, which realizes conduction and dissipates heat for the drain of the lower arm switch tube Q3 and the upper arm switch tube Q1; the second copper bar 5 realizes conduction and dissipates heat for the drain of the lower arm switch tube Q4 and the bridge arm switch tube Q2.

[0060] The lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are both formed by two SiC-MOSFET bare chips connected in parallel.

[0061] The structure of the negative DC bus copper bar 7 is the same as that of the positive DC conductive copper bar 1, both of which are radiator structures, used for conducting electricity while realizing heat dissipation of the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4, and the negative DC bus copper bar 7 and the positive DC conductive copper bar 1 are arranged correspondingly.

[0062] In the present invention, four conductive copper bars are simultaneously connected to the drain D and the source S of the SiC-MOSFET bare chip, providing a power loop for DC current and AC output, while realizing a double-sided heat dissipation method, and the thermal resistance of the inverter is low.

[0063] The SiC-MOSFET bare chip of the present invention adopts a non-bonding wire method on the copper substrate, and the gate driver output end is directly connected to the gate (G) and source (S) of the device, which shortens the wire length and reduces the parasitic inductance value of the driving loop. At the same time, all devices are welded to the copper substrate on a plane, and the system reliability is improved.

[0064] The DC and AC conductive copper busbars of the present invention are shared with the heat sink, and each switching device has a similar electrical and thermal circuit, which can reduce the thermal imbalance problem caused by asymmetric electrical and thermal parameters. It is easy to achieve thermal balance for parallel devices, and there will be no overheating failure problem due to different device temperatures, and the system reliability is high.

Claims

1. A SiC-MOSFET bare chip inverter structure with no bonding wire and double-sided heat dissipation based on a copper substrate, characterized in that: The invention comprises a copper substrate (2), and an upper bridge arm switch tube Q1, an upper bridge arm switch tube Q2, a lower bridge arm switch tube Q3 and a lower bridge arm switch tube Q4 connected to the copper substrate (2), and also comprises a positive DC conductive copper bar (1), a first copper bar (4), a second copper bar (5) and a negative DC bus copper bar (7), wherein the positive DC conductive copper bar (1) is connected to the drain electrodes D of the upper bridge arm switch tubes Q1 and Q2; the first copper bar (4) is connected to the drain electrode of the lower bridge arm switch tube Q3 and the source electrode of the upper bridge arm switch tube Q1; the second copper bar (5) is connected to the drain electrode of the lower bridge arm switch tube Q4 and the source electrode of the bridge arm switch tube Q2; and the negative DC bus copper bar (7) is connected to the source electrodes of the lower bridge arm switch tube Q3 and the source electrode of the lower bridge arm switch tube Q4.

2. The SiC-MOSFET bare chip inverter structure based on a copper substrate without bonding wires and double-sided heat dissipation according to claim 1, characterized in that: The copper substrate comprises a copper bottom layer and an insulating layer (3) on the copper bottom layer (6); the gate electrodes G of the upper bridge arm switch tube Q1, the upper bridge arm switch tube Q2, the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are insulated from the copper bottom layer of the copper substrate; the pins of the electrical components in the upper bridge arm switch tube Q1, the upper bridge arm switch tube Q2, the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are connected by single-layer PCB wiring; the source electrodes S of the upper bridge arm switch tube Q1, the upper bridge arm switch tube Q2, the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are directly connected to the copper bottom layer (6) of the copper substrate after being subjected to an electric and thermal separation process.

3. The SiC-MOSFET bare chip inverter structure based on a copper substrate without bonding wires and double-sided heat dissipation according to claim 2, characterized in that: The upper bridge arm switch tube Q1, the upper bridge arm switch tube Q2, the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are respectively connected to their corresponding gate drive circuits, and the gate drive circuits of the upper bridge arm switch tube Q1, the upper bridge arm switch tube Q2, the lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are all insulated from the copper bottom layer of the copper substrate, and the pins of each electrical component in the four gate drive circuits are connected by single-layer board PCB wiring.

4. The SiC-MOSFET bare chip inverter structure based on a copper substrate without bonding wires and double-sided heat dissipation according to claim 3, characterized in that: The positive DC conductive copper busbar (1) is designed as a heat sink structure.

5. The SiC-MOSFET bare chip inverter structure based on a copper substrate without bonding wires and double-sided heat dissipation according to claim 4, characterized in that: The upper bridge arm switch tube Q1 and the upper bridge arm switch tube Q2 are both formed by two SiC-MOSFET bare chips connected in parallel.

6. The SiC-MOSFET bare chip inverter structure based on a copper substrate without bonding wires and double-sided heat dissipation according to claim 5, characterized in that: The first copper bar (4) and the second copper bar (5) are arranged side by side, and the first copper bar (4) serves as a high-frequency AC output terminal connected to the drain of the lower bridge arm switch tube Q3 and the source of the upper bridge arm switch tube Q1; The second copper busbar (5) serves as another high-frequency AC output terminal and is connected to the drain of the lower bridge arm switch tube Q4 and the source of the bridge arm switch tube Q2.

7. The SiC-MOSFET bare chip inverter structure based on a copper substrate without bonding wires and double-sided heat dissipation according to claim 6, characterized in that: The first copper bar (4) and the second copper bar (5) have the same structure and are both configured as heat sink structures.

8. The SiC-MOSFET bare chip inverter structure based on a copper substrate without bonding wires and double-sided heat dissipation according to claim 7, characterized in that: The lower bridge arm switch tube Q3 and the lower bridge arm switch tube Q4 are both formed by two SiC-MOSFET bare chips connected in parallel.

9. The SiC-MOSFET bare chip inverter structure based on a copper substrate without bonding wires and double-sided heat dissipation according to claim 8, characterized in that: The structure of the negative DC busbar copper bar (7) is the same as that of the positive DC conductive copper bar (1), both of which are heat sink structures, and the negative DC busbar copper bar (7) and the positive DC conductive copper bar (1) are arranged correspondingly.

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