Discharge Current Optimization of Multiphase Pulsed Alternator Based on Excitation Compensation

Abstract

A pulsed alternator (PA) is an important pulse power source capable of driving many types of loads. For electromagnetic rail launcher load, the ideal driving current is a flat top wave. However, the discharge current of the PA will decline, resulting in the inability to maintain a flat top during pulse discharge. Therefore, an optimization method of discharge current based on excitation compensation is proposed and compared it with the traditional method of adjusting the trigger angle (ATA) in this article. First, the relationship between field current and discharge current is analyzed theoretically, and the optimization method is verified. Second, three optimization methods: ATA, separate-excitation compensation (SEC1), and self-excitation compensation (SEC2) were compared. Then, a comparative analysis was conducted on the optimization strategies for the combination of multimethods. Finally, the PA inductance parameters were extracted by using the finite element method (FEM), and the FEM and circuit coupling simulation and the circuit simulation were compared to verify the accuracy of the circuit model and the superiority of the optimization strategies. The results show that all three optimization methods have obvious merits and demerits. The optimization strategies can balance the merits and demerits of a single method and obtain great benefits at small costs. Especially the ATA + SEC2 and ATA + SEC1+ SEC2 optimization strategies are the most prominent. The former does not require external energy compared to the latter, at the cost of a slightly higher field current peak; the latter can achieve the recovery of residual energy in the rails for excitation compensation in the next pulse discharge, at the cost of requiring a set of devices for the residual energy recovery in the rails.