Stability assessment of AC hybrid power systems for ‘more electric’ aircraft

This paper analyses the small-signal stability of an AC hybrid power system for dasiamore-electricpsila aircraft. It consists of a synchronous variable frequency generator which supplies frequency insensitive AC loads, and high voltage DC (HVDC) loads via a 12-pulse transformer-rectifier unit. Various sub-system dynamics are derived and combined to form a complete system dynamic equation. The small-signal stability of the system under various operating conditions is assessed by evaluating eigenvalues of the Jacobian matrix of the linearised system. It has been shown that the system stability deteriorates as the power drawn by the motor drive load increases, and the load filter capacitance decreases.