一种低耦合电容的高压SiC MOSFET驱动隔离电源设计

AN ISOLATED GATE DRIVER POWER SUPPLY DESIGN FOR HIGH-VOLTAGE SiC MOSFET WITH LOW COUPLING CAPACITANCE

高压SiC MOSFET更快的电压变化率dv/dt,导致其驱动遭受更严重的共模干扰,而现有高隔离电压驱动电源大多又存在耦合电容高、共模瞬态抗扰度(CMTI)能力弱、转换效率低等问题,因此该文设计一种兼具高隔离电压、高转换效率的低耦合电容驱动隔离电源。首先,基于有源钳位反激变换器,提出一种驱动隔离电源耦合电容等效简化解析模型,并通过仿真、实验验证解析模型可行性;其次,基于该模型分析耦合电容影响因素及其优化方法,为低耦合电容的驱动电源设计提供参考;最后,通过实验评估所提低耦合电容高压SiC MOSFET驱动隔离电源性能。结果表明,该文驱动隔离电源额定转换效率约80%,工频耐压高达18 kV,且耦合电容不足2 pF,CMTI能力强。

Due to the faster dv/dt of high-voltage SiC MOSFET,the common mode interference of its gate driver is more serious.While most existing gate driver power supplies with high isolation voltage usually have the problems of high coupling capacitance,weak common mode transient immunity(CMTI)ability,low conversion efficiency and so on.Therefore,an isolated gate driver power supply with high isolation voltage,high conversion efficiency and low coupling capacitance is designed.Firstly,based on an active clamp flyback converter,this paper proposes a simplified analytical model for coupling capacitance,and the feasibility of analytical model is verified by simulations and experiments.Secondly,the influencing factors and optimization methods of coupling capacitance are analyzed,which provides references for the designs of low coupling capacitance gate driver power supplies.Finally,the performance of proposed high-voltage SiC MOSFET isolated gate driver power supply with low coupling capacitance is evaluated through experiments.The results show that its rated conversion efficiency is about 80%,and power frequency withstand voltage is up to 18 kV.In addition,the coupling capacitance of isolated gate driver power supply is less than 2 pF,so its CMTI capability is extremely strong.