Delivering High Power: The Role of the Pulse Waveform
High power industrial processes present some unique challenges to equipment designers, facility designers, and power electronics engineers. Large machines may have dimensions of tens, or even hundreds, of meters. They are typically situated in buildings with large highbays and bridge cranes overhead. Access for forklifts and other vehicles is provided in “keep clear” zones around the perimeter of the machine. An outcome that can be surprising is the location of the power supplies for the plasma processes. They can be located across the “keep clear” zones, with cable lengths of 30 m or more. This cable length, with typical inductance for realistic cables, provides a challenge for power delivery. This becomes really critical once the power exceeds 30 kW to 40 kW. As we developed the architecture for our Ascent DMS product, we addressed specifically this issue.
The waveform produced by the Ascent DMS was designed intentionally to overcome the challenge of delivering high power through an industrially realistic cable, considering length and inductance. The waveform, shown in the figure below, has an initial voltage boost segment, or pulse. The effect of the boost pulse is to create fast current rise, to effectively approximate a current square wave. This enables delivery of high powers required for industrial dual magnetron sputtering (DMS) processes, often in the range of 100 kW to 150 kW, or even higher. The effectiveness of our approach was first proven in our own industrial-grade dual magnetron sputtering system, followed by tens of field installations globally. You can learn more about the Ascent DMS here.