SiC MOSFET凭借其优异的性能,在高压电能变换领域有着广泛的应用前景。然而,在大电流等级下采用并联应用时,受电路参数和芯片参数差异的影响,并联芯片间存在电流分配不均衡的问题,由此导致并联芯片的结温差异,严重情况下引发可靠性问题并导致并联芯片失效。为了抑制并联芯片间的不均衡电流,该文首先分析了不对称布局下的并联芯片的动态电流分布特性,并建立了并联芯片电流分布与阈值电压之间的关联关系。然后,提出了一种SiC MOSFET多芯片并联动态电流均衡芯片分选方法,利用芯片阈值电压的分散性进行芯片分组,形成对不对称布局电路参数的补偿,从而减小并联芯片动态电流不均衡。最后,通过实验对所提方法进行了验证,结果表明采用所提分选方法可以显著提升并联SiC MOSFET的电流均衡特性。
Abstract
Silicon carbide (SiC) MOSFETs
with their superior performance
have broad application prospects in high-voltage power conversion fields. However
when employed in parallel configurations under high current conditions
differences in circuit parameters and chip characteristics may result in current imbalance among the parallel chips. This imbalance leads to junction temperature variations
which may cause reliability issues and
in severe cases
lead to failure of the parallel chips. To mitigate the current imbalance among parallel chips
this paper first analyzes the dynamic current distribution characteristics of parallel chips under asymmetric layouts and establishes the correlation between current distribution and threshold voltage. Subsequently
a dynamic current balancing chip sorting method for paralleled SiC MOSFETs is proposed. This method utilizes the dispersion in chip threshold voltages to group the chips
thereby compensating for the asymmetry in circuit parameters and reducing dynamic current imbalance. Finally
experimental validation is conducted
and the results demonstrate that the proposed sorting method can be adopted to significantly improve the current balancing performance of paralleled SiC MOSFETs.