Active thermal balancing strategy of three-level converters through stray parameters control in laminated busbars

Abstract In high-power three-level converters, busbar stray inductance critically influences switching transient and thermal distribution. This paper establishes a parametric stray inductance model for laminated busbars and analyses its impact on commutation paths. To resolve thermal imbalance, a power loss thermal balance method optimizes control strategies, enabling stable commutation path switching and preventing system instability at switching points. The key is to propose weighting factors based on stray parameters for dynamic energy exchange among internal, external and clamp switches, combined with case temperature-dependent modulation to achieve thermal balance in three-level converters. The accuracy of the model established and the feasibility of the adopted approach are verified by simulation studies in MATLAB/Simulink and experiments based on a 900 V alternating current power system.