Study on the Impact of Machine Parameter Variations on Performance of Modular Pulsed Alternator Power System

Abstract

As the muzzle energy in the electromagnetic launch increases, it becomes necessary to use a modular pulsed alternator power system composed of multiple pairs of machines connected in parallel. In practical situations, however, parameter variations between two machines are inevitable, and it has uncertain effects on the system performance. Furthermore, due to pulsed alternators driving railgun through a rectifier, the system connection scheme has two options: 1) two machines are connected in parallel before connecting them to the rectifier and 2) two machines are connected in parallel after connecting them to the rectifier. The sensitivity of two topologies to the parameter variations is also uncertain. To make sense of this uncertainty, the impact of machine parameter variations on the system performance is investigated. This paper is performed on the simulation of a pair of pulsed alternators driving a railgun, using one-factor-at-a-time method to observe the system performance in the parameter variations. The sensitivity of two topologies is analyzed taking into account small variations in machine manufacturing parameters—rotor inertia, field winding, and armature winding and in machine control parameters—rotor speed and rotor angle. The results reveal that the system performance is more sensitive to the machine control parameters compared with the machine manufacturing parameters, especially the initial offset in the rotor angle. Furthermore, the connection scheme in which two machines connected in parallel before connecting them to the rectifier is the more robust and is less sensitivity to parameter variations compared with the other topology. This paper is aimed at the identification of the most sensitive parameter and the more robust topology to provide support for the further application.