Design and Analysis of a Two-Phase Two-Axis-Compensated Compulsaor

As power supplies, compulsators are popular choices for electromagnetic railguns. In this paper, a two-phase two-axis-compensated compulsator (2P2AC compulsator) with lower internal inductance and higher power density was designed and analyzed. Two-phase armature windings are allocated on the stator, and discharge pulse currents to the load via a rectifier. This arrangement decouples the machine speed from the pulsewidth, thus enables a higher tip speed. Two sets of windings with electrical orthogonal displacement are allocated on the rotor. The bigger one is the field winding that freewheels via a diode and provides the direct-axis compensation during the discharge process, while the smaller one is the short-circuit compensating winding providing the quadrature-axis compensation. The effect of the composition of the d- and q-axis compensation is equivalent to a passive compensation using a continuous conductive shield, which compresses the flux for all rotor positions. Compared with the passive compensation, this arrangement has no conductive path to couple with the field winding due to the orthogonal displacement, thus speeding up the charging process. This paper presents the design methodology of the 2P2AC compulsator, along with its system performance of driving railgun load.