Research On Influence Factors And Control Method Of Gate Voltage Uniformity Of Press-pack IGBT Chips

The power semiconductor device,which is widely used in the whole process of power collection and grid connection of renewable energy,AC/DC transmission and networking,flexible application of power,is the key component for manufacturing various high-voltage high-capacity power converters and controllers of the power grid.Press-pack IGBT devices have the advantages of double-sided heat dissipation,short circuit of failure,and are easy to be connected in series,therefore they are more suitable for all kinds of high-voltage and large-capacity equipment in smart grid.Considering the general background of China's economic development and energy demand,the development of high-voltage high-power press-pack IGBT devices with high-reliability,inherent ruggedness and intellectual property rights is of great significance for China's industrial upgrading and power grid construction.In order to improve the current capability of press-pack IGBT devices,a device is usually packaged and integrated with dozens of IGBTs and FRDs.Therefore,the current sharing regulation among a large number of parallel IGBT chips integrated in the device has become one of the difficulties in device development.The chips in the press-pack IGBT device are driven by the drive printed circuit board(hereinafter referred to as the "drive board")inside the device.Inconsistent parasitic parameters of the drive board will cause the gate voltages of the IGBT chips to be inconsistent during the transient process,and the chips to be turned on at different time,resulting in the transient non-uniform current of the parallel chips.Based on the core subject of current sharing,combined with practical development demand of the domestic high-voltage high-power IGBT device,aiming at the drive board structure as well as the operation condition in large-scale parallel encapsulation,the characteristics,modeling method and regulation of the application of the drive board are deeply studied by adopting the experimental measurement and theoretical calculation methods.Firstly,an integrated circuit model including the drive source,the chip model and the drive board is established.The variation law of gate voltage and the transient response characteristics of the drive board during the chip opening process are studied.The influence of gate circuit resistance,gate interior resistance and gate-emitter capacitance on the gate voltage uniformity of chips is revealed by circuit calculation.Secondly,the gate voltage uniformity condition(hereinafter referred to as the"uniformity condition")is proposed,and its validity is verified by experiments.Based on the proposed uniformity condition,drive board regulation method—the inductance matching method,chip number matching method,concentrated resistance compensation method and loop wiring method are proposed to improve the gate voltage uniformity.Finally,the multi-layer PCB is applied to the design of the drive board of the press-pack IGBT device.In order to reduce the dispersion of the parasitic parameters of the drive board among parallel chips and improve the uniformity of the gate voltage,a four-layer drive board design scheme is proposed for the press-pack IGBT device.The equivalent circuit model of the four-layer drive board is established,the principle of the board wiring and consistent control of gate voltage is analyzed.The paper acquires the influence of gate circuit resistance,gate interior resistance and gate-emitter capacitance on the gate voltage uniformity of chips when applying the multilayer drive board,thus its effectiveness is verified.