Design of the Motion control for a test rig analyizing Rotation and Expansion performing assemblies in parabolic trough collector power plant applications

Kurzfassung

Parabolic Trough Collector (PTC) power plants collect the sun’s energy as heat. The heat can be stored and used to produce electrical energy or process heat. PTCs are the widest spread Concentrated Solar Power (CSP) technology. Elementary components in PTC power plants are Rotation and Expansion Performing Assemblies (REPAs). These REPAs serve to establish a connection between the expanding and rotating Heat Collection Element (HCE) and the rigid tubing system. Since REPAs are elements that are subjected to high stress levels a test rig is built, allowing investigation on durability and REPA failure. The task to perform realistic durability tests in an accelerated manner, leads to special requirements on the motions executed by the test rig. The present bachelor thesis describes the development of the motion control system for the REPA test rig. To provide a better understanding of the context a brief overview of CSP, PTC and REPA technologies is given. Subsequently, know-ing the requirements, the design of the test rig is presented. In the main part of the thesis the arrangement of the motion control, its integration in the Supervisory Control and Data Acqui-sition (SCADA) system, as well as the chosen hardware is discussed. Further on, the pro-grammed functions and the specifications of the motion control system are described. The development process led to a system enabling the test rig to reproduce a translational mo-tion in a 45° range and a rotational motion between -120° and +90°. Whereby these motions are produced using cylinders, which are controlled by a hydraulic unit. To control the speed of the motion and enable the execution of 0.25° steps in the rotation axis a Variable Speed Drive (VFD) and a servo motor with servo controller are driving two separated hydraulic pumps. The motion functions, implemented on a SIMATIC S7-300 Programmable Logic Controller (PLC), enable the above described motions as well as a positioning at position set points. The correct function of the developed system is not yet verified. A discussion of the influence of the PLC cycle time and a comparison with an existing PTC system is carried out. Ultimately a summary of the motion control parameters and specifications are given.