基于SiC BJT典型双电源阻容驱动电路的开关过程分析及损耗最优的实现

Switching process analysis and loss optimal implementation based on SiC BJT typical dual-supply RC drive circuit

为降低碳化硅(SiC)双极型晶体管(BJT)开关过程中的总损耗,针对SiC BJT典型的双电源阻容驱动电路,研究了考虑回路寄生参数情况下SiC BJT的详细开关过程,分析了加速电容对Si C BJT开关损耗和驱动损耗的影响,推导出了加速电容对SiC BJT开关过程各阶段持续时间的数学关系。理论分析表明,随着加速电容的增大,SiC BJT的驱动损耗成比例上升,而对开关损耗的优化并不明显。实验测试了加速电容从3. 3nF到94nF变化时SiC BJT的开关波形,并对加速电容变化时的SiC BJT的驱动损耗以及开关损耗进行了对比。实验结果表明,随着加速电容的增大,开关过程中的总损耗呈现先减小后增大的趋势,通过合理选取加速电容值,能够有效降低SiC BJT开关过程的总损耗。

In order to reduce the total loss in the switching process of SiC BJT. This paper studies the detailed switching process of SiC BJT considering the loop parasitic parameters based on the SiC BJT dual-source driver with resistor and capacitor. Then,the influence of the accelerating capacitance on the switching loss and drive loss of SiC BJT is analyzed and the mathematical relationship between the accelerating capacitance and the duration of the SiC BJT switching process is deduced. The theoretical analysis shows that as the accelerating capacitance increases,the driving loss of SiC BJT increases proportionally,while the switching loss decreases less. Finally,the switching waveform of SiC BJT was determined experimentally at various accelerating capacitance values from 3. 3 nF to 94 nF. In addition,the driving loss and switching loss of the SiC BJT are compared. From power loss measurements,it was found that with the increase of the accelerating capacitance,the total loss in the switching process first decreases and then increases. The total reduction of the overall loss in the SiC BJT switching process can be achieved through properly selecting the accelerating capacitance.