A High-Voltage Pulsed Power Supply With Online Rise Time Adjusting Capability for Vacuum Tubes

Vacuum tubes such as gyrotrons and magnetrons require a specific range of high-voltage pulse rise time for their proper operation. Otherwise, unavoidable operation modes or even arcs may take place in the vacuum tubes. Hence, the capability of the adjustable output pulse rise time is very promising for pulsed power supplies when they are dedicated to vacuum tubes. This article proposes a high-voltage series stacked insulated gate bipolar transistor (IGBT) switch with rise time adjusting capability to evolve the pulsed power supply abilities. The rise time adjustment is carried out using a low-voltage ramped shape signal provided for all the IGBTs via a multi-winding transformer. In this way, the IGBTs are turned on as fast as possible with specific delays. The sequential turn on process of the IGBTs forms the output pulse rising edge. Unlike the extant strategies for controlling the turn on speed of the IGBTs, the dissipated power of the proposed method is negligible. The power associated with adjusting the output pulse rise time is recovered to the pulsed power supply using a simple and low-voltage dc/dc converter. The proper performance of the proposed structure is evaluated using simulations and experimental prototyping.