A Flexible Waveform Conditioning Strategy of an Air-Core Pulsed Alternator

Abstract

As a new type of pulsed power supply, an air-core pulsed alternator concentrates all the functions of energy storage, energy conversion, and power conditioning in one machine. It is also easy to condition the output voltage and current waveforms. These advantages make it a promising compact power supply system for the electrothermal-chemical gun (ETCG). However, the use of multiphase air-core pulsed alternators as the power supply of ETCGs may give rise to problems such as generating high voltage trigger pulse and providing proper voltage and current waveforms. According to the special requirements of ETCGs, a novel circuit topology and a flexible waveform conditioning strategy of an air-core pulsed alternator were proposed. In the initial stage of the discharge process, the two-phase armature windings are connected in series to generate a high voltage pulse to ignite the capillary. The series mode does not need a high-voltage capacitor and its charger to ignite the capillary, which makes the whole system more compact. After the capillary is ignited, the two-phase armature windings are connected in parallel. Adding conditioning inductors and controlling the trigger angles can make the voltage and current waveforms more flexible. The mathematical model of the two-phase air-core pulsed alternator was established to obtain the basic relationship of the variables. Based on the mathematical model and the circuit topology, the performances of the ETCG powered by the alternator using the flexible waveform conditioning strategy were analyzed. The results indicate that with the new strategy of the air-core pulsed alternator it is feasible to provide more flexibility in pulse conditioning than with the conventional strategy.