PhD sets new standards

Industrial PhD sets new standards in solar cell production


Dr. Parsa Rahmanpour has recently defended his PhD work with the title «Model-based Control of the Czochralski Silicon Crystal Pulling Process» at the Norwegian University of Science and Technology with professor Morten Hovd and Steinar Sælid as supervisors.

Parsa has investigated and applied a new control structure for an essential process in the manufacture of silicon bars/ingots. This process, the Czochralski process, is key to solar cell production. Solar cell based energy production is growing quickly, and in 2017 is expected to near 400 Gigawatts. The annual growth rate is over 20%, and about a third of new solar power is through monocrystalline solar cells. This means millions of kilograms of monocrystalline silicon can be produced better/faster with the help of the introduced control structure.

The central challenge in the work was creating a mathematical model of the process. Enhanced control algorithms were also required to manage the process more efficiently than with conventional methods. The results from this work will improve the production of silicon ingots through reduced production costs and increased volume, along with improved and more consistent quality.

The resulting algorithm and regulation structure is implemented in APIS, which is Prediktor’s in-house environment for real-time data processing. The solution and communication interface are now ready for evaluation against a crystal puller and eventual industrial implementation.

An important point of this methodology, is that the suppliers of crystal puller machines can keep their method of controlling the pullers confidential. The work therefore gives the possibility of automating the optimization of those control algorithms.

The work has been completed in cooperation with Prediktor and NTNU, through financing from the Norwegian Research Council. The Norwegian Research Council established an Industrial PhD as a pilot in 2008, where the goal was to increase researcher recruitment in industry. Financing of doctorate education has benefitted many areas. An Industrial PhD isn’t a new type of doctorate, but it has a focus on industry, on bringing a scientific level of quality to help production grow.

According to the Norwegian Research Council, Industrial PhDs increase the cooperation between companies and research institutes. Which allows for more research into industrial matters and educates researchers in fields that are relevant to the businesses they work for.

Parsa is currently an employee with Prediktor AS in Fredrikstad, where he works with advanced process control.

Prediktor has, since 1995, delivered advanced industrial IT tools and solutions to a large number of industries. Our products and solutions and based on our employees’ solid process knowledge and insight into customer’s business challenges and needs. Prediktor delivers products to partners or complete solutions to end customers.