When multiple SiC MOSFETs are paralleled, the differentiation of internal parameters can lead to imbalanced currents in the parallel branches, causing individual devices to overcurrent and even damage. Existing current sharing technologies and methods suffer from issues such as parameter drift, poor dynamic performance, and high system complexity. To enhance the reliability and stability of parallel current sharing, this paper first analyzes the unbalanced current distribution caused by transient and steady-state modes under parallel switching conditions, obtaining the internal parameters of the devices and the external circuit parameters, and extracting the key parameters for transient and static current imbalance. Secondly, a method for autonomous current sharing in four branches based on the merging approach of coupled inductance is proposed. The magnetic coupling effect of the coupled inductance in the equal distribution of current is deeply analyzed theoretically, and the magnetic and circuit parameters of the coupled inductance are optimized. Finally, parallel simulation and experimental testing in the branches of a three-phase rectification circuit show that the current balance achieved with merged inductance is below 1%, and the scheme has been verified to have superior robustness under load disturbance.