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Q&A with Barry Mather: Bridging the Gap from Power Electronic Devices to Systems

September 28, 2018

Barry Mather

Barry Mather is the group manager for Integrated Devices and Systems within NREL’s Power Systems Engineering Center.

As the group manager for Integrated Devices and Systems (IDS) within NREL’s Power Systems Engineering Center and chair of the Institute for Electrical and Electronics Engineers (IEEE) Power Electronics Society Denver chapter, Barry Mather considers himself an honest broker—balancing the needs for a reliable grid while also increasing the amount of distributed energy resources (DER) integrated into the grid. Having been at the lab for more than 8 years, one of Mather’s first projects at NREL was to evaluate how utilities could use smart inverters to mitigate the impacts of utility-scale solar systems interconnected to the distribution grid. As he described, “back in 2010, smart inverters were a new thing.”

That project—which was the first utility-scale demonstration of smart inverters in the nation—led Mather to visualize the intersection where integrated devices and systems meet, with “one foot in power systems and one foot in power electronics.” Mather sat down to answer some questions about his career at the lab and research in his group. The following has been edited for length.

How would you describe your “specialty”?

If I had to pick, it would be working at that junction of power electronics and power systems. My academic background is in the design of power electronics, and my experience at NREL has led to a deep understanding for how utilities plan, model, and operate a system—and what their concerns are. That's the specialty of the Integrated Devices & Systems research group I lead at NREL. It's working at that junction of actual devices and what we're really trying to do on the power systems side. 

What else can you tell me about the Integrated Devices & Systems research group?

IDS is focused on four things: power electronics development and design for new, renewable connections, energy storage, grid interface equipment, as well as controls of those devices; standards for the interconnection of DER; advanced testing and evaluation at the ESIF; and providing technical input to state regulators and utilities for DER interconnection. Those four things are quite different but really it requires an understanding of each to have a cohesive understanding of the utility research space. 

How is NREL’s work in interconnection standards impactful for industry?

We provide unbiased and validated information to help people who are working on the standards make more informed decisions. Because we understand the power electronics side of the world, we know the tradeoffs and difficulty that a vendor might have in providing some of the device functionality requested by a utility. But we also understand the utility side—and why they might want some functions and features. We can bridge that gap between the two and offer our input to help achieve a compromise between what is needed and what is possible.

How does your involvement with IEEE influence your work at NREL?

I've been the chair of the Denver chapter of the IEEE Power Electronics Society for more than 6 years, and it’s been valuable for me in terms of my career and NREL's connection to the Denver chapter. It allows me to keep connected to the more traditional power electronics applications and research that's going on, which is important, even though the applications might be different compared to the research we’re doing here. It’s also a good way to represent NREL as electronics experts within that community.

What are you most excited about right now?

We have an exciting Laboratory Directed Research and Development project that I'll be leading focused on new ways to synchronize 100% renewable energy system microgrids, or really just power systems. Synchronization is one of the big issues. How do we synchronize a system without a large synchronous machine somewhere in the system? If we're going to get to 100%, it’s crucial to figure out how to synchronize all these inverter-based generators together so that they operate in concert with one another, form the grid, and operate the power system. 

Another project coming in this year, funded by Solar Energy Technologies Office, is very interesting. In the past much of our work has focused on the voltage-related issues of DER integration and not much research has been done related to protection issues, but we now have a project that's working on an advanced method for detecting system faults within a distribution system, without relying on traditional overcurrent protection. This will use what's called “traveling wave detection techniques,” and it's very challenging. It's getting us situated to deal with some of the protection-level impacts, not just by new protection methods but also by the implementation of those methods within power electronic devices. This gets at the idea of autonomous grids, where a lot of these roles and functions for the grid are incorporating more and more control as they’re distributed out onto the system and put into power electronic systems like inverters, as opposed to individual components like individual breakers and relays. A lot of that functionality will all be integrated in the future into power electronic devices.  

What are some of the biggest challenges and opportunities in your line of research?

The biggest opportunity is to see our work help enable higher and higher amounts of renewable energy systems. At the end of the day, that's what most people at NREL are here for. The standards are also very visible. We see how those directly impact the industry and all the vendors. A lot of the other work we do, like advanced testing, also eventually becomes very routine and we can get to a point where we can stop doing it because others are taking over those processes and they become mainstream.

One of the challenges is trying to provide all these grid functions and services from inverter-based generation without increasing the price. This is where a lot of fundamental power electronics work is still valuable to keep pushing the price down. Things like wide-band gap semiconductors offer potential advantages. Even though they might be more expensive right now, over a 30-year investment timeframe like a utility is accustomed to planning for, they are likely a good investment. This is a fairly mature research area, so we have to be more and more creative about how we're going to keep the downward cost pressure on the power electronics side of the PV systems.