Discussion on the discharging effects of two STRETCH meat grinder modules with different triggering delays

The STRETCH meat grinder is one typical inductive pulsed power supply circuit for electromagnetic launch system. It has remarkable current amplification ability as a single unit, but one module cannot provide enough amplitude and width for load current of the railgun launching. This article discusses the effects of different triggering delays on the load current with two STRETCH meat grinder modules. In order to reduce the magnetic field coupling between two modules, the two main switches are opened simultaneously. In order to make the load current waveform with no notch, the thyristor of the first module is triggered when its pulse forming capacitor is fully reversely charged. For the thyristor of the second module, we consider several time points of triggering delay. Because of the practical constraint for the maximum rail current which ensures no rail erosion, the rectangular waveform is the most appropriate load current waveform. So the comparing criterion can be defined as the ratio of the load current waveform area and its maximum rectangle area at different current levels. Higher ratio means that the current is more like a rectangular wave and is better accordingly. Based on the above criterion and extensive simulation researches, we found that the best delay time is the moment when the capacitor reversely charging the inductor completely. This research and the result are of great theoretical significance for further study on the collaborative triggering of multiple STRETCH meat grinder modules.