PC-based control for the photovoltaic production
Harnessing the power of the sun has become big business. Over the last decade, the photovoltaic industry has developed worldwide into a dynamic, high-growth market. Alongside other renewable energies, the conversion of sunlight into electrical energy has increasingly become the focus of attention for environmentally-conscious politics and has been promoted extensively by market introduction programs in Japan and Germany. At the heart of every photovoltaic system are the solar cells, which convert the radiation energy contained in sunlight directly into electrical energy.
The traditional raw material used to manufacture solar cells is high purity silicon (Si). It is used in two forms, as crystalline silicon (c-Si) and as amorphous silicon (a-Si). Accordingly, a distinction is made in solar cell production between crystalline technology and thin-layer technology. In the crystalline process, solar cells are manufactured in several production steps from silicon wafers, so-called solar wafers. The individual solar cells are subsequently combined to form a solar module in order to achieve a higher performance.
In the amorphous thin-layer technology, the silicon is applied directly to a large glass plate or a metal or plastic film – which becomes the solar module. The interior structure of the amorphous silicon provides the means for absorbing the sunlight. Cadmium telluride (CdTe), copper indium diselenide (CIS) and copper indium gallium diselenide (CIGS) are increasingly being used alongside amorphous silicon as raw materials for the thin-layer technology. In order to protect the solar modules against mechanical stresses and weathering influences, they are embedded between two glass or plastic sheets that are held by a metal frame or left as a frameless laminate.
For photovoltaic systems to make a truly meaningful contribution to the world’s energy supply in the long term, continual cost reductions are essential over the next few decades. PC-based control technology from Beckhoff can make a significant contribution to the reduction of production costs for solar wafers, cells and modules. As an open and flexible automation solution, it can be used in all areas of the photovoltaic industry. With Industrial PCs, EtherCAT I/O Terminals and fieldbus components, drive technology and TwinCAT automation software, Beckhoff offers a scalable, modular control concept that provides an ideal solution for every task in the creation of photovoltaic products: wafer cutting technology and inspection, saw damage etching, texture etching, diffusion, phosphor glass etching, anti-reflective coating, metallisation, classification, transport and storage systems, as well as stringer and lamination lines.
Continuity and flexibility via PC-based control technology
Beckhoff implements open automation systems on the principle of PC-based control technology. This openness in relation to the software and hardware interfaces enables the machine manufacturers to continually adapt their systems to different requirements at low cost.
Beckhoff solutions for the photovoltaic industry
The open, scalable TwinCAT automation software of Beckhoff is a software PLC and Motion Control solution for PCs. Programming in accordance with the international IEC 61131-3 standard guarantees high investment security for machine manufacturers. The utilisation of technological standards based on the Windows operating system opens up numerous expansion options and allows the user to benefit from the rapid development of the computer industry.
Maximum performance up to the I/Os
Beckhoff supplies a complete range of fieldbus components for all common I/O and fieldbus systems. With the IP 20 Bus Terminals and the IP 67 Fieldbus Box modules, the entire range is available for all signals relevant to the photovoltaic production.
XFC technology – EtherCAT fully exploited
The pre-conditions for technological leadership in photovoltaic business are ever more powerful control components. EtherCAT, the fast Ethernet-based fieldbus, offers optimum real-time properties for critical process phases without the need for special hardware in the central processing unit. With the XFC technology (eXtreme Fast Control Technology), a time resolution of < 100 ns is possible using the time stamp method; sensor signals can be read with sampling times of 10 μs. This increases reproducibility and accuracy of movements.
In recent years, operational safety and work safety have played an ever larger part in machine construction. With TwinSAFE, Beckhoff offers a uniform system solution for optimum synergy between automation and safety technology. TwinSAFE integrates safety functions in the existing controller architecture.