Vehicle-mounted SiC DCDC converter and new energy vehicle

Abstract

The invention provides a vehicle-mounted SiC DCDC converter, which comprises a shell, a cover body, and a reactor, a main control circuit board, a contactor circuit board and a thin film capacitor which are arranged in the shell, and also comprises at least one power device, at least one power device switching PCB, a laminated busbar, a driving circuit board and a spring vibrating needle, wherein the power device switching PCB is correspondingly arranged on the surface of the power device, pins of a grid electrode G and a source electrode S of the power device are welded with the power device switching PCB to form a first welding point, the position of the first welding point is transferred on a plane perpendicular to the pins through wiring on the power device switching PCB, the contact surface of the first welding point is enlarged through a bonding pad, and a bonding pad contact surface is formed; the laminated busbar is arranged above the power device switching PCB, and the source electrode S and a drain electrode D of the power device are welded with the laminated busbar to form a second welding point; the driving circuit board is arranged above the laminated busbar, and the driving circuit board is fixedly connected with the shell; and the tail end of the spring vibrating needle is welded on the driving circuit board and is arranged on the side, which is opposite to the laminated busbar, of the driving circuit board, and the head end with compression deformation of the spring vibrating needle is compressed by the driving circuit board and penetrates through the laminated busbar to be elastically pressed and connected to the contact surface of the bonding pad, so that elastic connection is realized.

Description

technical field [0001] The invention relates to the field of SiC DCDC converters, in particular to a vehicle-mounted SiC DCDC converter. Background technique [0002] At present, in the application of new energy vehicle DCDC converters, commonly used switching devices are mainly divided into two categories according to the semiconductor materials used: IGBT switching devices represented by Si semiconductor materials and SiC MOSFET power devices represented by SiC semiconductor materials. SiC power devices have the advantages of high blocking voltage, low on-state resistance, small switching loss, and high temperature resistance. Volume, weight, and noise; at the same time, the reduction of on-state loss and switching loss can further reduce the design difficulty and size and weight of the cooling plate of the DCDC converter, and realize the miniaturization, light weight, low noise, and high efficiency of the DCDC of the new energy vehicle. SiC power devices will become a tr...

AI Technical Summary

Problems solved by technology

[0008] 2) The diameter of the source S pin, the drain D pin and the gate G pin is φ1.15mm. The pins are suitable for soldering circuit boards, and then coated with copper foil through the PCB. The current carrying of a single pin is about 25A or more. Thick copper foil is more difficult and costly. The larger area of ​​copper foil laying increases the volume of DCDC and the current carrying capacity is unevenly distributed. The current carrying capacity is not enough, and heat dissipation is difficult, causing the copper foil to burn;

[0009] 3) The drive control PCB board is welded to the gate G and source S pins, and it is extremely difficult to mass-produce, install, maintain and replace the drive control PCB board

[0010] 4) When multiple power devices are connected in parallel, due to the difference in the spatial arrangement of the devices, the paths from the drive signal to the gate G and source S pins are different, the parasitic inductance values ​​of the paths are different, and the switching delays of the parallel power devices are different, resulting in multiple parallel connections. Individual power devices cannot share current, and individual power devices generate severe heat, which reduces the overall power density of DCDC

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