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Bringing down BOS costs: An interview with Ideal Power Converters Vice President of Business Development Paul Bundschuh

Paul Bundschuh
Paul Bundschuh

Paul Bundschuh has served as vice president of business development for Ideal Power Converters since 2009. Mr. Bundschuh is responsible for business planning, funding raising, strategic partnerships, and sales/marketing for the firm. Under his leadership IPC has received $1M from the State of Texas Emerging Technology Fund as well as funding from Battery Ventures and several angel investors. His efforts also lead to IPC being awarded a $2.5M U.S. Department of Energy ARPA-E grant.

Prior to his experience in power electronics for renewable energy, Mr. Bundschuh worked in the semiconductor industry for over 20 years. He began and lead teams developing new technologies and geographic sales regions including at AMD, Motorola Semiconductor and Waves Audio.

His strong background in signal processing technologies, market development, and business strategy are being utilized by Ideal Power Converters in their efforts to establish an entirely new electronic power converter technology for photovoltaic inverters and other clean energy applications.


Solar Server: Can you describe some of the technologies that allow Ideal Power Converters to drastically reduce inverter size?

Paul Bundschuh: We have developed a new power converter topology. What this means is we use conventional materials and components, but the way the power switches and other components are arranged, and particularly how the power flow is controlled, is very different than what's ever been done before.

We have several granted U.S. patents and a long list of additional U.S. and international pending patents protecting our intellectual property. Our initial patents are basic patents, in that they don’t build on the work of others, but create an entirely new field in power converters.

There are a number of unique aspects and advantages about what we are doing. One of the ones that we emphasize is that we are able to eliminate approximately 95% of the magnetic material in these products. The magnetics are the most expensive items on the bill of materials, so this reduces our manufacturing costs significantly.

The magnetics consist of transformers and inductors that are manufactured from copper wires and steel cores. These commodity metal materials are near record highs and are likely to continue increasing. Additionally Chinese suppliers dominate this supply chain, so we also reduce our dependency on these manufacturers and have much higher percentage of domestic content than even other U.S. power converter manufacturers.


Solar Server: Along with this reduced size, are there other trade-offs?

Paul Bundschuh: There are a large number of other benefits. We discussed lower materials and manufacturing, but we also have a huge advantage in shipping and installation costs. Since our weight is 90% lower, 94 lbs. for IPC’s 30kW inverter versU.S.1200 lbs. for a conventional 30kW PV inverter, our customer’s shipping and installation costs are reduced by 90%.

This is very important, particularly for commercial-scale PV installations, because these are installed on existing buildings with limited space. It's always a challenge for installers to figure out where they are going to place huge conventional inverters. In several potential commercial PV installations, the entire project is cancelled, because of the lack of physical space for the large inverter.

Conventional commercial-scale PV inverters weigh thousands of lbs., and are shipped by freight trucks. They require a forklift just to be removed from the freight truck, which usually has to be brought in to the site on another separate truck. Once removed from the freight truck the massive inverters are mounted on engineered concrete pads. These are normally outside, because they are too big to put anywhere else. Additional structural enclosures are often required around the inverter for security or for architectural aesthetics.

In contrast IPC’s 94 lb. inverters are delivered by UPS or FedEx Ground in reusable shipping containers. They easily wall-mount with two individuals - inside, outside or even on the roof. This also allows the inverters to be placed closer to the PV arrays on the roof, which reduces costs of DC wiring materials, labor as well as wiring losses.

There are a huge range of logistics benefits by reducing the size and weight. Additionally our product is more efficient, and more reliable than conventional systems.


Solar Server: Do you have a CEC rated efficiency?

Paul Bundschuh: We are finishing that work right now, we expect to have a 97% CEC- weighted efficiency.


Solar Server: Can you comment on your company's progress towards UL1741 certification, and the path to commercial rollout of this technology?

Paul Bundschuh: Certainly. We are making great progress on UL1741 and IEEE1547 certification. We have been working closely with Intertek, the leading Nationally Recognized Technology Laboratory in the U.S. for PV inverter certifications for more than a year on these certifications. IPC is finishing the last final steps, and we will be done with that in a matter of weeks if not sooner.


Solar Server: Your company notes that installation costs are rapidly becoming the largest portion of PV system costs. Can you comment more on this, and how you believe your system will reduce installation costs?

Paul Bundschuh: Certainly. Well, when people think about PV systems they traditionally think about the cost of the modules, because they are pretty visible, you can see them on the roof or wherever the installation is.

But the cost of PV modules has plummeted. They are, in high volumes, around a dollar per watt, a year ago they were twice that price, and four years ago they were four times that price. So the price of the modules has plummeted.

If you look at the cost of these systems over a long period of time, such as a decade, the cost of the modules has actually been following a learning curve cost reduction path similar to Moore's Law, which is well known in the semiconductor industry. This silicon semiconductor cost reduction has driven huge advantages in communications and computing industries over the last several decades. The cost reduction or learning curve effect of PV modules is very similar to what we have seen in the semiconductor industry.

Now that's very exciting, and we expect that trend to continue. The problem today really isn't about the PV modules. The problem is that the cost of the PV modules has declined so much, but the rest of the system really hasn't. The industry and the DOE has recognized that the cost challenge in solar has shifted from modules to non-module costs.

The price of the PV modules have traditionally been more than half of the system cost, and just a few years ago it was two-thirds of system costs. Today it is about one-third, and it is dropping to even less than that.

The non-module costs are called Balance-of-Systems or BOS. Hardware BOS costs include inverter, racking and wiring, but reducing the Soft BOS costs is the biggest challenge for the industry to reach widespread cost-parity with fossil fuels. The bulk of the Soft BOS is labor, including design, permitting, and installation. IPC feels our simple, modular inverter design dramatically simplifies that whole process.

It's really one of logistics. We talked before about the smaller size and weight. On some of our initial installations in Central Texas, our customers, these are PV installation companies, have told us that they saved fifteen to twenty cents per watt, on lower shipping and installation with our inverter installation. That is in the ballpark of half the inverter costs for installations in Texas.

When we look at the cost savings on shipping and installation of IPC’s inverter in Hawaii, we have determined that the indirect cost savings can be greater than the price of the inverter. Another way to look at that is, if our competitor's products were free, they may not be cost-effective in Hawaii because of all of these additional shipping and installation costs.


Solar Server: What types of warranty does Ideal Power Converters offer?

Paul Bundschuh: We are offering a standard 10-year commercial warranty. IPC’s product is inherently more reliable than conventional inverters, since we have eliminated all electrolytic capacitors and made other improvements that limit the lifetime of inverters.


Solar Server: Is there anything else that we haven't covered that you think is important for our readers to know about your product and the issue of installation costs?

Paul Bundschuh: The technology and products that we've talked about have been developed by a small team of engineers independently of any federal funding. We have however recently been awarded a $2.5M DOE ARPA-E (Advanced Research Project Agency – Energy) grant, to further reduce size, weight and cost of our product. We are working with two leading universities, Rensselaer Polytechnic Institute and Virginia Tech.

With the assistance of these two universities, we will develop a new type of power semiconductor switch component. As mentioned earlier, IPC uses conventional materials and components including off-the shelf silicon IGBTs (Insulated Gate Bipolar Transistor) and diodes. But we have a unique requirement in our topology that other's don't to use bi-directional or AC switches.

IPC’s initial product uses four components, two IGBTs and two diodes, to construct a bi-directional switch.

With our -E grant, we will develop a bi-directional silicon IGBT switch, which will reduce from 4 silicon chips to 1 to support our switch needs. It will also further reduce our costs and improve our weighted efficiency to 98.5%, which will be unsurpassed in the industry by either transformer or transformer-less inverters.

And furthermore, we expect to use this same typology not only in PV inverters, but in bi-directional battery chargers, bi-directional high-power electric vehicle charges, wind power converters and many other applications.


Interview by Solar Server International Correspondent Christian Roselund