2015 Award Winners
Award-winning project: Raw data analysis and precise efficiency measurement of electric drives
Project partners: Hottinger Baldwin Messtechnik GmbH, Darmstadt | Steinbeis Transfer Center Energy-Efficient Power Electronics for Electric Drives and Storage, Aschaffenburg
In order to reduce electricity consumption in industry, households and road transport, the demands placed on the energy efficiency of electric drives are constantly increasing. Precise measuring instruments, measurement methods and analytical procedures are required to evaluate optimisation measures aimed at improving the efficiency of electric machines and power converters.
The Steinbeis Transfer Centre for Energy-Efficient Power Electronics for Electric Drives and Storage Systems at Aschaffenburg University of Applied Sciences and Hottinger Baldwin Messtechnik GmbH, based in Darmstadt, driven by high customer demands from real-world applications and the aim of simultaneously recording and processing electrical and mechanical measurement values in real time, have jointly derived and practically implemented the specifications for the measuring instruments and data analysis.
In order to carry out energy efficiency measurements in an application-oriented manner and obtain meaningful results, a measurement concept for time-varying load points was adopted. The Steinbeis team first optimised the current measurement for electrical power measurement on drive systems powered by power converters. High-precision load resistors were developed and tested, and precisely adapted to the Genesis HighSpeed data recorder series from HBM in terms of both electrical data and mechanical dimensions. The accuracy of these resistors is 0.02 per cent within the relevant frequency range.
Furthermore, analysis methods were developed to determine other important parameters of electrical machines and drives. For example, it is now possible to calculate the air-gap torque of a rotating-field machine as a time-dependent curve using the raw data from current and voltage measurements, processed with the Perception software. With the calculated air-gap torque, it is easy to assess the dynamic characteristics and the accuracy of the drive control.
A demonstrator was developed to explain and demonstrate these measurement methods and types of analysis to interested specialists. This consists of a complete drive test bench featuring a test and load machine, frequency converters and a full suite of sensors. One challenge was to minimise the weight and size of the demonstrator so that it could be checked in as hold luggage.
Thanks to the successful collaboration between Steinbeis and industry – recognised with the Steinbeis Foundation’s Transfer Prize (Löhn Prize) – it was possible to rapidly enter new sectors and markets. Some of the results of this transfer project have been presented in scientific publications and lectures and are being incorporated into the doctoral theses of two research assistants at the university. Both project partners anticipate further interesting project initiatives in the field of efficiency improvement in the future.