Princeton Power Systems seeks to maximize and control the energy produced by solar panels
By: Lauren Otis
As anyone with a basic knowledge of solar power generation knows, things would be ever so simple if every day was clear and sunny. But they aren’t. Which is where a company like Princeton Power Systems comes in.
Princeton Power makes what are called grid-tied inverters for renewable energy. A grid-tied inverter is something like a black box which takes raw power output from a solar panel or wind turbine and allows it to be exported into the general power supply the "utility grid."
Solar panels generate DC power, so on the most basic level an inverter needs to convert DC to AC power to allow it to enter the general power supply, said Darren Hammell, Princeton Power’s CEO and co-founder of the tech startup along with Eric Limpaecher and Mark Holveck. All three co-founders graduated from Princeton University in 2001 with engineering degrees, and started Princeton Power that same year. In addition to making power converters, Princeton Power produces variable speed motor drives and military power supply systems, aiming to increase efficiencies in the use of and production of electrical power.
Converting raw solar power to AC is just the beginning, Mr. Hammell said. "There are different (computer) algorithms and different control methods that allow us to get more power out of the same panels," Mr. Hammell said. The voltage and current coming out of a panel can be controlled by the converter, with voltage being set at a level to maximize the current, what is called the maximum power point, he said.
Unfortunately, with solar intensity and the raw power output of a solar panel always fluctuating especially in areas like New Jersey with fickle weather patterns the maximum power point is always changing too, Mr. Hammell noted. And if the voltage is set at the wrong level, a solar power system will operate at much less than optimum efficiency.
So the critical question is "how do you get at that maximum power point all the time?" said Mr. Hammell. Although Princeton Power has developed computer algorithms for its converters, "we’ve never tested them on a real solar array in New Jersey’s weather conditions," he said.
Now thanks to a $330,000 grant from the New Jersey Commission on Science and Technology, Princeton Power will be able to do just that. And, according to Mr. Hammell, they will be able to enlist the services of several Princeton University professors to develop faster and better algorithms for their converters under the terms of the grant, which call for an academic/business partnership in the research.
Princeton Power’s was one of four proposals which the NJCST announced it would fund giving out a total of $ 1.3 million in May, after weighing 29 proposals from around the state. NJCST is seeking to both benefit high technology entrepreneurs and science researchers in institutions of higher learning in New Jersey by bringing them together in such joint projects.
With the grant, Princeton Power intends to install a 10 kilowatt solar array on a building on Princeton’s campus, and work with Sanjeev Kulkarni, a professor in the Department of Electrical Engineering, and Clancy Rowley, an assistant professor in the Department of Mechanical and Aerospace Engineering, as well as with a team of both graduate and undergraduate engineering students, on developing optimal power conversion under New Jersey weather conditions, said Mr. Hammell.
"I’m optimistic. I hope we get some nice results," said Mr. Kulkarni, who will bring his expertise in statistical pattern recognition, machine learning, adaptive systems and signal processing to bear on the project.
"I think it’s a great opportunity to get academic research tied in with a product," Mr. Kulkarni said. The project "is a nice application (of his research) so I will learn something," he added. "It’s a nice cross-fertilization."
Mr. Rowley, whose field of specialization is in the control of fluid systems, said he too was excited at the prospect of using his research knowledge to benefit a worthy private-sector initiative. "I’ve always been excited to apply this knowledge towards improving environmentally good power generating systems, like solar and wind power," he said.