Research on Novel Control Strategies for Three-Phase Inverters in Railway Passenger Vehicles

To meet the demands of flexible configuration of three-phase loads and the use of variable-frequency air conditioning in railway passenger vehicles, this paper designs a novel control strategy for three-phase inverters under unbalanced and nonlinear load conditions. This strategy enhances the ability to control output voltage unbalance and suppress output voltage harmonics. The new control strategy employs a dual-loop voltage and current control based on feedforward decoupling, improving dynamic response characteristics. It decomposes the voltage and current into positive and negative sequence components and controls them separately, maintaining output voltage symmetry under unbalanced loads. Additionally, a quasi-resonant controller is incorporated to suppress specific harmonics, reducing the total harmonic distortion (THD) of the output voltage under nonlinear loads. The paper first introduces the main circuit principles of the three-phase inverter for railway passenger vehicles, then focuses on analyzing the control algorithms included in the new strategy, and finally verifies the feasibility and effectiveness of the proposed control strategy through simulations.