Active Current Balancing Scheme for Steady-State Operation of Parallel IGBTs in Hybrid Circuit Breakers

Hybrid circuit breakers (HCBs) have emerged as a pivotal technology in modern power systems, combining mechanical and solid-state elements to enhance performance. A critical challenge in HCBs is ensuring balanced current distribution among parallel Insulated Gate Bipolar Transistors (IGBTs) during steady-state operation. This paper proposes a novel daisy-chained architecture with synchronized current measurements for achieving Active Current Balancing (ACB) in multiple parallel IGBTs. The proposed methodology employs real-time monitoring of collector current combined with precise control of gate drive signals to ensure uniform current distribution among parallel IGBTs. Concurrent activation of ACB across all IGBTs can lead to undesirable current transients. To mitigate this, an algorithm for sequential ACB loop activation is developed, aiming to minimize excessive current transients by optimizing the activation sequence of IGBTs. The scheme is validated through comprehensive Ltspice simulations, which demonstrate significant improvements in the current imbalance.