Experimental investigations on the trigger characteristics of a cold-cathode plasma discharge switch with grid voltage control

The cold-cathode plasma discharge switch is a switching device capable of conducting and interrupting currents. It has the potential to replace fully controllable power semiconductor devices in the field of direct current power transmission. The switch primarily consists of four electrodes: anode, control grid, source grid, and cathode. By applying voltage to the source grid, a magnetized source plasma is generated. Applying a positive voltage to the control grid facilitates the charged particle motion, forming a stable conduction path from anode to cathode. Conversely, applying a negative voltage to the control grid creates a sheath within the grid's apertures to achieve current interruption. We developed a flat-type cold-cathode plasma discharge switch and investigated the effects of source plasma discharge current, electrode spacing, and anode voltage on its trigger characteristics. This type of plasma switch relies on control grid voltage to regulate plasma, and the trigger time is largely determined by the charged particle motion. The source plasma provides a sufficient supply of charged particles, which is essential for switch conduction. Reducing the “source grid–control grid” gap can significantly shorten the trigger time. Increasing the anode voltage enhances the electric field strength across the gap, accelerating the charged particle motion into the “anode-control grid” region. The impact of the control grid current on switch performance and the mechanism for low-voltage plasma conduction are discussed. Additionally, further device miniaturization is necessary to enhance insulation strength on the left side of the Paschen curve and reduce its trigger time.