Dynamic performance improvement of aircraft PM generator system with a composite control strategy

Purpose The purpose of this paper is to address the dynamic performance improvement of DC-link voltage for permanent magnet generator (PMG) systems under constant power load (CPL). Design/methodology/approach Firstly, the sliding mode control (SMC) with the exponential rate reaching law is adopted in the outer voltage loop to improve the DC-link voltage dynamic performance and the robustness of parameters variation. Secondly, the chattering phenomenon of the command torque current on the sliding mode surface is analyzed. Thirdly, the two degrees of freedom (TDOF) control is utilized in the inner current loop, and there are two sets of coefficients, which are the system-tracking coefficient and the antidisturbance coefficient. Findings The system-tracking and the antidisturbance performance can be adjusted independently when the SMC is adopted in the voltage loop and the current loop adopts the TDOF control. The command torque current is filtered by the system-tracking function of the TDOF control, which reduces the fluctuation of load current under CPL and improves the stability of the PMG system. Originality/value In this paper, the mechanism of the SMC and the TDOF control is studied and analyzed, which improves the tracking performance and antijamming ability of the command torque current.