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In recent surveys, PCB designers named high voltage among the issues causing problems in their designs. That led us to speak with Zuken USA’s Andy Buja, Wilmer Companioni, and Sanu Warrier about the challenges PCB designers and design engineers must confront when working with high-voltage designs.
In this conversation, we discuss everything from the nuts and bolts of high-voltage design, such as the need to separate components of a high-voltage board, to the compliance problems companies like Tesla face when installing EV chargers around the world in countries with varying regulations.
Andy Shaughnessy: Zuken has been involved in the automotive side of things for a long time, and with EVs becoming more popular, we’re seeing challenges with higher voltages and voltage switching. Would you talk about the challenges of designing high-voltage boards?
Wilmer Companioni: This is a combination of both high speed and high voltage, which is intriguing to me. When we’re talking EVs, there are several different implementations. There are the 48-volt systems and the mild hybrids, and there are 600-volt designs for the traction inverters.
Andy Buja: One of our former CADSTAR resellers was a high-voltage and power supply engineer in the aerospace industry, working primarily for Moog. During a Joint Strike Fighter collaboration effort, they were working with some high-end voltages for the flap systems that were tweaking up as high as 8,000–10,000V because of high-altitude issues. When we’re dealing with aerospace, now they’re really breaking the envelope as far as getting so much on a small board. The whole idea was to continue to utilize the 3D aspect that would lead to creepage and clearance spacings when you would have literal holes with grooves cut in the board to increase the spacing between contact points or between other conductors.
Barry Matties: You need physical separation?
Buja: Exactly. It is like taking a Dremel and then cutting a hole right through the board so that the voltage would float around the opening of the hole rather than taking the shortest route between two points.
Matties: That must have been a challenging board to design and build.
Buja: When he showed it to me, it was in pretty classic shapes. Some of them were an actual “S” shape that they had cut in there. They had used a finite analyzer and gone through the process of cutting these in between the transformers and some very large diodes. The only real way to solve it, in essence, is creepage and clearance. And we’ve also put that inside of our mainstream solution, eCADSTAR.
Sanu, how is it looking on your end, as far as high voltages incorporating higher gauge cabling from the customers that you’re dealing with? Are you separating out high-voltage cables?
Sanu Warrier: I deal with most of the electrical side and the cables and harnesses side of it. On the cable and harness design side, EV design has not added new challenges. Well, there are always new challenges, but it’s sort of taking it from one industry and taking it to the other. So, for example, we’ve always had high-voltage design when it comes to multiple thousand kVs being designed at some of our customers for our utilities, for example. But taking that and miniaturizing that has been a challenge on the board.
To read this entire conversation, which appeared in the January 2022 issue of Design007 Magazine, click here.