A Dynamic Current Balancing Method for Multichip SiC MOSFET Modules with Separate Gate Drive Structures

Dynamic current imbalance between parallel dies due to asymmetric layout will limit the available capacity of power modules. In high current modules such as 1000A modules, the number of parallel dies increases further and the traditional dynamic current balancing method may be difficult to achieve the ideal effect. In this paper, a separate gate drive structure is implemented to effectively suppress the unbalanced dynamic current within SiC multichip modules. By incorporating a pair of gate and kelvin terminals for each group of dies, the power and gate loops can be completely decoupled and the dynamic current balancing can be achieved. First, the mechanism of dynamic current imbalance is analyzed and based on which the separate gate drive structure is proposed. The module as well as the gate driver for two dies in parallel are fabricated and the effectiveness of the proposed method has been verified through simulations and experiments. Finally, the significance of the proposed method and future applications in industry taking into account economic factors is discussed.