In this Bachelor’s thesis, we present the process of building two learning models with frequency-controlled electric motor drives and the parameterization of the master/follower direct connection of drives with the ACS880 series of frequency converters.
In the first part, we created two learning models intended for teaching the use of frequency converters to future generations of students. We described the characteristics of the ACS380 and ACS480 series of ABB frequency converters that we had available in the laboratory and the two identical asynchronous motors that the frequency converters will drive. We designed and assembled two constructions from the Minitec's aluminium profile system and assembled the control panels, from which we will manage the operation of the learning platform and the frequency converter. The result are two very useful devices which will be helpful in the future learning process.
As a demonstration of more advanced functionality of high-end frequency converters, we performed the synchronization of two drives without additional hardware or external controller with ABB ACS880 series, which stands as a reference among industrial frequency converters. We are able to do this since there are two identical units available in our laboratory, which drive two similar asynchronous motors. The measuring station where the frequency converters and motors are located was the Master's thesis of a former student Jaka Karo \cite{karo}. The goal was to have both systems behaving identically by only controlling the first (master) frequency converter and making the second unit with a separate drive as a follower, and to keep the rotor in exactly the same position all the time. The obtained functionality is also called electrical shaft and these frequency converters are supposed to be capable of such precise control. It turned out that this is not possible in our configuration because our frequency converters have installed the standard firmware which only offers the option to synchronize by speed or torque reference. To achieve the desired synchronization precision, we should purchase the specific position control firmware, which then sends rotor position references to the following drive.
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