Separated Disturbance ADRC with Bus Capacitance Adaptation for Voltage Control of Dual Three-Phase PMSGs

The dual three-phase permanent magnet synchronous generator (DTP-PMSG) is a promising candidate for the electrical starter/generator (ESG) in more electric aircraft, owing to its low DC bus voltage ripple and high reliability. However, in generation mode, ESG control faces challenges due to disturbances from varying engine speeds and diverse load conditions. Additionally, the total DC bus capacitance, critical for voltage loop gain, is difficult to determine at the ESG equipment level and varies with system conditions. To address these issues, this paper proposes a bus-capacitance-adaptive separated disturbance active disturbance rejection control (SD-ADRC) method tailored for the DTP-PMSG. The study begins by analyzing the power flow of the ESG system, establishing an accurate DC bus voltage control model. It then examines the shared issues of lumped disturbance ADRC (LD-ADRC) and SD-ADRC, particularly in parameter design, tracking performance, and disturbance rejection. Comparative analysis reveals that SD-ADRC outperforms LD-ADRC in disturbance handling. The impact of bus capacitance mismatch on closed-loop performance and disturbance rejection is analyzed, and an online capacitance identification method using short-time q-axis current injection is integrated into the SD-ADRC framework to ensure the desired control performance. The feasibility and effectiveness of the proposed method are validated through experiments.