Transient performance of linear induction launchers fed by generators and by capacitor banks
Abstract
Computer simulation is used to investigate the transient performance of induction-type coilguns as a function of the dimensions, material properties, type of supply, firing sequence of switching elements, and connections of drive coils. The performance of both generator-driven and capacitor-driven coilguns is addressed. It is shown that the generator-driven coilgun performs satisfactorily in the starting section. However, at high velocity, the transit time is close to the electrical transient time constant, and therefore the DC components produce a retarding force. To avoid this problem, the three phase voltages should not be switched on simultaneously, but rather phase-by-phase according to their zero current crossing points. The capacitor-driven coilguns derive the alternating current needed to create a traveling wave from resonance with the inductance of the coils. Therefore, the initiation of the sinusoidal current oscillation coincides with the switch-on time. They are ideally suited for short-time, high-acceleration operation, but they are likely to require higher operating voltages than the generator-driven coilguns, because of the constraint imposed on the capacitance by the resonance condition with attenuation.
- Publication:
-
IEEE Transactions on Magnetics
- Pub Date:
- January 1991
- DOI:
- 10.1109/20.101099
- Bibcode:
- 1991ITM....27..585H
- Keywords:
-
- Capacitors;
- Computerized Simulation;
- Electromagnetic Acceleration;
- Magnetic Coils;
- Magnetic Induction;
- Surges;
- Linear Systems;
- Traveling Waves;
- Electronics and Electrical Engineering