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Evaluation of Economical Impact of Energy Optimization Functions in VFDs for Industrial Applications
KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
2011 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

Electric motor systems are the most important types of loads which consume up to 70% of total consumed electricity in industry, so the reduction of energy  consumption in electric motor systems has become an important goal for all countries. In many of these applications, big energy savings are possible if the motors operate at variable speeds rather than at a fixed speed. This is made possible by using of variable frequency drives ―VFD‖. VFDs are capable of operating the different types of motors at variable speeds, thus maximizing the energy savings in different industrial applications and recovering the additional costs of VFDs within several years. Many motor drive manufacturers are now developing their new drives with advanced functions like ―Energy Optimization function‖ in order to even further reduce the energy consumption. Most of these manufacturers claim that the power consumption by the electric motors can be reduced further by more than 20-30% at partial load conditions. The main purpose of this study is to evaluate the efficiency performance of motor drives and the effects of their energy optimization functions on energy savings for different application cases. Four drives are tested and evaluated for the ―energy optimizing‖ functions. The efficiency performance of each drive is measured in a laboratory setup driving an induction motor for different combinations of operating speeds and loads. The results from efficiency measurements are then used to evaluate the economic impacts of the energy efficiency functions available in these drives. Based on the efficiency test results, four drives are assumed to be applied into three different typical applications including a pump application, a ventilation application and an elevator application. According to different applications and different load cycles, energy required by each drive for these applications is evaluated on yearly basis and energy saved by EO functions is calculated, which is then represented in terms of reduction in CO2 emission and reduction in energy bill. The efficiency comparison in typical applications provides an easy way to observe the efficiency performance of each drive and also demonstrates what is the most suitable application for each drive and the relevance of its energy optimization function.

Place, publisher, year, edition, pages
2011. , 74 p.
EES Examensarbete / Master Thesis, XR-EE-EME 2011:003
National Category
Engineering and Technology
URN: urn:nbn:se:kth:diva-53666OAI: diva2:470582
Educational program
Master of Science - System-on-Chip Design
Available from: 2012-01-19 Created: 2011-12-29 Last updated: 2012-03-15Bibliographically approved

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