Control Strategy for a Brushless Synchronous Generator based Active Rectifier regulated DC Power System with minimal DC-link capacitance for More Electric Aircraft

This paper proposes control improvements to minimize the DC link capacitance value in a brushless synchronous generator (BSG) based active rectifier regulated aircraft DC power system. The active rectifier regulates the DC-link voltage, achieves unity power factor (UPF) and, low Total Harmonic Distortion (THD) current at the BSG output. The improved excitation control of BSG aids during transient load conditions to meet MIL-STD-704F transient specifications at the active rectifier output 270V DC with reduced DC-link capacitance. The field optimization technique helps to maintain UPF operation at the BSG output during steady-state operation. The proposed strategy is modeled and verified for a 25kW DC power system using Controller Hardware-in-loop (C-HIL) testing and results show that the proposed strategy helps to achieve a fast transient response to meet MIL-STD-704F with minimal DC-link capacitance.