A three-level silicon carbide motor controller

Abstract

A three-level silicon carbide motor controller, including a controller housing, the middle of the side wall of the controller housing is provided with a partition, the partition divides the controller housing into upper and lower cavities, the front end of the partition is provided with a three-phase copper bar mounting hole, the rear end of the partition is provided with a filter mounting hole, a filter is installed in the filter mounting hole, a capacitor assembly accommodation hole is arranged on the partition, a silicon carbide module is installed at the corresponding position of the bottom of the partition in the upper cavity of the controller housing, the positive and negative levels of the silicon carbide module face the capacitor assembly accommodation hole, a film capacitor is arranged in the lower cavity of the controller housing, the positive and negative levels of the capacitor of the film capacitor in the lower cavity of the controller housing pass through the capacitor assembly accommodation hole and are welded and fixed with the positive and negative levels of the silicon carbide, an intermediate level is arranged at the connection between the positive and negative levels of the silicon carbide and the capacitor, the upper end of the intermediate level is welded and fixed with an intermediate gasket, and a control panel is arranged above the silicon carbide module.

Description

Technical Field

[0001] This invention relates to the field of motor controllers for new energy vehicles, and specifically to a three-level silicon carbide motor controller. Background Technology

[0002] The rapid iteration and upgrading of new energy commercial vehicles, industrial servo equipment, and special electric drive equipment means that the performance of the motor controller, as the core of the power system, directly determines the overall operating efficiency, control accuracy, and reliability. Early silicon-based IGBT two-level motor controllers were limited in their development for high-voltage, high-efficiency, and high-power-density applications due to material properties and topology constraints. Now, with the widespread adoption of high-voltage electric drive systems, stringent requirements are placed on the power conversion efficiency, output waveform quality, anti-interference capabilities, and power density of motor controllers. Traditional topologies and device solutions cannot adequately meet the performance upgrade demands of high-end electric drive systems, necessitating breakthroughs from new technologies. Traditional two-level topologies are prone to problems such as insufficient device withstand voltage, high output voltage harmonics, and high system losses in high-voltage scenarios, directly impacting the vehicle's range and lifespan. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies by providing a three-level silicon carbide motor controller. By jointly optimizing both the power topology and the material characteristics of the power devices, the controller significantly improves overall operating efficiency, control accuracy, and long-term reliability under high-voltage platform conditions, while simultaneously achieving a synergistic upgrade in power density, heat dissipation performance, electromagnetic compatibility, and overall structural stability.

[0004] The objective of this invention is achieved through the following solution: A three-level silicon carbide motor controller includes a controller housing. A partition is provided in the middle of the side wall of the controller housing, dividing the controller housing into upper and lower cavities. A three-phase copper busbar mounting hole is provided at the front end of the partition, in which a three-phase copper busbar is installed. A filter mounting hole is provided at the rear end of the partition, in which a filter is installed. A low-voltage interface is provided on the side of the filter. A capacitor assembly clearance hole is provided on the partition. A silicon carbide module is installed at a corresponding position at the bottom of the upper cavity partition of the controller housing. The positive and negative voltage levels of the silicon carbide module face the capacitor assembly clearance hole. A thin-film capacitor is provided in the lower cavity of the controller housing. The positive and negative voltage levels of the thin-film capacitor pass through the capacitor assembly clearance hole and are welded and fixed to the positive and negative voltage levels of the silicon carbide module in the lower cavity of the controller housing. An intermediate voltage level is provided at the connection between the positive and negative voltage levels of the silicon carbide module and the positive and negative voltage levels of the capacitor. The upper end of the intermediate voltage level is welded and fixed to an intermediate gasket. The output end of the silicon carbide module is connected to the three-phase copper busbar, and the input end of the thin-film capacitor is connected to the filter. A control board is provided above the silicon carbide module.

[0005] The lower end face of the silicon carbide module is provided with neatly arranged pin-fin needle-shaped fins, and cooling water channels are provided on the outer side of the pin-fin needle-shaped fins. The cooling water channels are sealed by water channel sealing rings.

[0006] The positive and negative voltage levels of the silicon carbide and the capacitor are fixed by laser welding, and the upper end of the middle voltage level is fixed to the middle pad by laser welding.

[0007] The lower end of the intermediate level is connected to the positive and negative levels of the capacitor, and the upper end of the intermediate level is connected to the positive and negative levels of the silicon carbide through an intermediate spacer.

[0008] The thin-film capacitor is fixed to the controller housing by bolts, the silicon carbide module is fixed to the controller housing by bolts, and the control board, three-phase copper busbar and filter are fixed to the controller housing by bolts.

[0009] Hall sensors are integrated on the three-phase output side of the silicon carbide module.

[0010] The intermediate pad is a copper sheet.

[0011] The advantages of this invention are: 1. For the power devices of the motor controller, both the topology and material properties are optimized. The characteristics of the three-level topology and silicon carbide devices are used to improve the high voltage resistance of the components, reduce the power device loss, optimize the sinusoidal output waveform, make the motor run more smoothly, improve the overall vehicle conversion efficiency, and increase the range. 2. By selecting silicon carbide (SiC) power devices, the intrinsic advantages of third-generation semiconductor materials are fully utilized to replace traditional silicon-based IGBT devices. SiC devices possess higher breakdown electric field strength, faster switching speed, and lower switching and conduction losses, significantly increasing the upper limit of the controller's switching frequency and widening the high-efficiency operating range. This results in lower system losses and higher energy conversion efficiency at the same power level. Simultaneously, the heat dissipation solution for SiC utilizes pin-fin heat dissipation, which, combined with the excellent high-temperature resistance of SiC devices, greatly improves the controller's adaptability to various operating conditions and long-term operational reliability, solving the problems of performance degradation and reliability decline of traditional silicon-based IGBT devices under high-temperature conditions. 3. The three-level topology architecture, compared to the traditional two-level topology, significantly reduces the voltage stress on power devices, decreases output voltage harmonic content and current ripple, optimizes output waveform quality, reduces the risk of overvoltage at the motor terminals and motor body losses, and improves system operating efficiency and control accuracy. A simple copper pad solution reduces space occupancy, and laser welding enhances welding strength and precision, providing a feasible and reliable solution for implementing three-level motor controllers. Furthermore, the three-level topology is adaptable to high-voltage, high-power motor drive scenarios, offers superior system electromagnetic compatibility, significantly reduces the need for external filtering components, and simplifies electrical circuit design. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is an exploded view of the structure of the present invention; Figure 3 This is an assembly diagram of a silicon carbide module and a thin-film capacitor. Figure 4 This is a schematic diagram showing the positions of the silicon carbide module, thin-film capacitor, and controller housing. Figure 5 This is a schematic diagram of a three-level connection; Figure 6 This is a schematic diagram of the bottom structure of a silicon carbide module; Figure 7 This is a schematic diagram of the upper surface structure of the silicon carbide module; Figure 8 This is a schematic diagram of the controller housing structure; Figure 9 This is a schematic diagram of a three-level T-type structure. Detailed Implementation

[0013] like Figures 1 to 9As shown, a three-level silicon carbide motor controller includes a controller housing 3. A partition 3-2 is provided in the middle of the side wall of the controller housing 3, dividing the controller housing 3 into upper and lower cavities. A three-phase copper busbar mounting hole 3-3 is provided at the front end of the partition 3-2, in which a three-phase copper busbar 11 is installed. A filter mounting hole 3-4 is provided at the rear end of the partition 3-2, in which a filter 6 is installed. A low-voltage interface 7 is provided on the side of the filter 6. A capacitor assembly clearance hole 3-1 is provided on the partition 3-2. A silicon carbide module 10 is installed at the corresponding position at the bottom of the upper cavity partition 3-2 of the controller housing 3. The lower end face of the silicon carbide module 10 is provided with neatly arranged pin-fin needle-shaped fins. Cooling water channels are provided on the outer side of the pin-fin needle-shaped fins, and the cooling water channels are sealed by a water channel sealing ring 5. Hall sensors 13 are integrated on the three-phase output side of the silicon carbide module 10. Integrating the Hall sensors 13 onto the silicon carbide module 10 saves space compared to traditional structures. The silicon carbide positive and negative voltage level 10-1 of the silicon carbide module 10 faces the clearance hole 3-1 of the capacitor assembly. A thin-film capacitor 2 is installed in the lower cavity of the controller housing 3. The positive and negative voltage level 2-1 of the thin-film capacitor 2 on the front cover plate 1 passes through the clearance hole 3-1 of the capacitor assembly and is welded to the silicon carbide positive and negative voltage level 10-1. An intermediate voltage level 12 is set at the connection between the silicon carbide positive and negative voltage level 10-1 and the capacitor positive and negative voltage level 2-1. The upper end of the intermediate voltage level 12 is welded to the intermediate spacer 9, which is a copper sheet. The silicon carbide positive and negative voltage level 10-1 and the capacitor positive and negative voltage level 2-1 are fixed by laser welding, and the upper end of the intermediate voltage level 12 is fixed to the intermediate spacer 9 by laser welding. The lower end of the intermediate level 12 is connected to the positive and negative level 2-1 of the capacitor, and the upper end of the intermediate level 12 is connected to the positive and negative level 10-1 of the silicon carbide through the intermediate spacer 9. The output end of the silicon carbide module 10 is connected to the three-phase copper busbar 11, the input end of the thin film capacitor 2 is connected to the filter 6, and a control board 8 is installed above the silicon carbide module 10. The thin film capacitor 2 is fixed to the controller housing 3 by bolts, the silicon carbide module 10 is fixed to the controller housing 3 by bolts, and the control board 8, the three-phase copper busbar 11, and the filter 6 are fixed to the controller housing 3 by bolts.

[0014] The assembly process is as follows: The film capacitor is installed from the bottom into the pre-set mounting cavity inside the customized housing and secured with bolts, ensuring a reliable rigid connection between the film capacitor and the housing base. Next, the silicon carbide module is installed from the top into the pre-drilled position in the housing and secured with bolts. A sealing ring is used to create a full-circumferential seal between the mounting surface of the silicon carbide module and the water channels inside the housing, preventing coolant leakage. The cooling method employs a direct water-cooling solution with pin-fins, eliminating traditional heat exchange structures such as thermal pads and transition heat sinks. The coolant directly flows through the internal cooling water channels and the pin-fin enhanced heat exchange structure, contacting the core heat dissipation surfaces of the silicon carbide module and film capacitor. This significantly increases the heat exchange area and efficiency, fully releasing the high-frequency, low-loss, and high-temperature performance advantages of silicon carbide devices, and adapting to the low-ripple and high-balance operation requirements of three-level topologies. After securing, the positive and negative terminals of the silicon carbide module and the film capacitor are soldered separately using laser welding, which provides higher precision and strength at the weld seam compared to tin soldering. After completing the positive and negative voltage level soldering, place an intermediate spacer at the midpoint between the silicon carbide module and the film capacitor, and connect the intermediate voltage level using laser soldering. Then, install the control board and three-phase motor busbars into the housing from top to bottom. Connect the output terminal of the silicon carbide module to the motor's three-phase busbars, and connect the filter assembly to the input terminal of the film capacitor. Use bolts to secure the control board, three-phase motor busbars, and filter to the housing. Finally, install the low-voltage interface to complete the assembly of the entire motor controller.

[0015] This motor controller, based on a customized motor controller housing, achieves comprehensive optimization of efficiency, power density, and operational stability through multiple structural and topological innovations. Its core lies in employing a three-level power topology to improve the sinusoidal output waveform, reduce motor harmonic losses, achieve balanced bus voltage distribution, and reduce the voltage withstand pressure of individual power devices. Combined with the inherent advantages of silicon carbide power devices—low loss, superior high-frequency characteristics, and resistance to high temperatures and pressures—it significantly reduces system switching losses and improves overall conversion efficiency. This provides a novel technical solution with a reasonable structure, superior performance, and high reliability for the high-performance integration and large-scale industrial application of motor controllers for high-voltage, high-power new energy commercial vehicles and special electric drive equipment.

[0016] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications made to the present invention by those skilled in the art without departing from the spirit of the present invention shall fall within the protection scope of the present invention.

Claims

1. A three-level silicon carbide motor controller, comprising a controller housing (3), characterized in that: A partition (3-2) is provided in the middle of the side wall of the controller housing (3), dividing the controller housing (3) into upper and lower cavities. A three-phase copper busbar mounting hole (3-3) is provided at the front end of the partition (3-2), and a three-phase copper busbar (11) is installed in the three-phase copper busbar mounting hole (3-3). A filter mounting hole (3-4) is provided at the rear end of the partition (3-2), and a filter (6) is installed in the filter mounting hole (3-4). A low-voltage interface (7) is provided on the side of the filter (6). A capacitor assembly clearance hole (3-1) is provided on the partition (3-2). A silicon carbide module (10) is installed at the corresponding position at the bottom of the upper cavity partition (3-2) of the controller housing (3). The silicon carbide module (10) has positive and negative voltage levels (10). -1) Facing the capacitor assembly clearance hole (3-1), a thin film capacitor (2) is set in the lower cavity of the controller housing (3). The positive and negative voltage levels (2-1) of the thin film capacitor (2) pass through the capacitor assembly clearance hole (3-1) and are welded and fixed to the positive and negative voltage levels (10-1) of silicon carbide. An intermediate level (12) is set at the connection between the positive and negative voltage levels (10-1) of silicon carbide and the positive and negative voltage levels (2-1) of capacitor. The upper end of the intermediate level (12) is welded and fixed to the intermediate pad (9). The output end of the silicon carbide module (10) is connected to the three-phase copper busbar (11). The input end of the thin film capacitor (2) is connected to the filter (6). A control board (8) is set above the silicon carbide module (10).

2. The three-level silicon carbide motor controller according to claim 1, characterized in that: The lower end face of the silicon carbide module (10) is provided with neatly arranged Pin-Fin needle-shaped fins, and cooling water channels are provided on the outer side of the Pin-Fin needle-shaped fins. The cooling water channels are sealed by water channel sealing rings (5).

3. The three-level silicon carbide motor controller according to claim 1, characterized in that: The positive and negative voltage levels of silicon carbide (10-1) and capacitor (2-1) are fixed by laser welding, and the upper end of the intermediate voltage level (12) is fixed by laser welding to the intermediate pad (9).

4. The three-level silicon carbide motor controller according to claim 1, characterized in that: The lower end of the intermediate level (12) is connected to the positive and negative levels (2-1) of the capacitor, and the upper end of the intermediate level (12) is connected to the positive and negative levels (10-1) of silicon carbide through the intermediate pad (9).

5. The three-level silicon carbide motor controller according to claim 1, characterized in that: The thin-film capacitor (2) is fixed to the controller housing (3) by bolts, the silicon carbide module (10) is fixed to the controller housing (3) by bolts, and the control board (8), the three-phase copper busbar (11) and the filter (6) are fixed to the controller housing (3) by bolts.

6. The three-level silicon carbide motor controller according to claim 1, characterized in that: Hall sensors (13) are integrated on the three-phase output side of the silicon carbide module (10).

7. The three-level silicon carbide motor controller according to claim 1, characterized in that: The intermediate pad (9) is a copper sheet.

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