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Adjustable Speed Drive Control Methods: Creating a Flatter Motor Efficiency Curve for More Energy Savings
Dr. Allen Neciosup
, Senior Applications Project Engineer, Motors & Drives Division, Toshiba


The need for higher operating efficiencies is being approached by new super energy efficient motors. For example, Super Premium Efficiency motors (IE4) have 20% less power loss than IE3 motors. In addition, Adjustable Speed Drives (ASDs) are becoming a part of the future of electrical machines for the many benefits they bring.  One benefit is the proven energy savings as they vary the speed of applications running in constant torque mode with even more savings available to variable torque applications. However, a large number of industrial ASD applications are still running on IE3 and even IE2 high efficiency motors. This presentation will discuss the overall system efficiency improvement that can be achieved when using a standard IE3 premium efficiency induction motor with an ASD with an energy optimized control algorithm. We will also go through an overview of standard motor control methods that industrial ASDs offer, their application, limitations, potential motor drive system issues when misapplied, and how some drives can add a higher energy savings when an adaptive control algorithm is applied. A comparison of the efficiency performance curves when a variable torque load  is run from an ASD with a conventional control method including vector, versus a drive with an adaptive energy optimized control algorithm are examined. Test results confirm that a significant improvement in power savings can be achieved.


Dr. Allen Neciosup, PhD earned his MSEE and PhD in technical sciences in the faculty of Cybernetics of St. Petersburg University, St. Petersburg, Russia. He started his career developing mathematical models and simulations of pseudo stochastic systems. During his overseas career, Allen worked with highly reliable fault and noise tolerant pseudo stochastic systems existing in the defense sector. In the USA, he has worked in medium and low voltage solutions for steel mills, mining, subsea, oil and gas industries including cycloconverters, static VAR compensators, and motors and adjustable speed drives. At present, Allen works at Toshiba International Corporation in the role of a senior technical advisor to the sales and marketing group. Allen has worked on special projects including customized product for the arctic tundra, and research into efficiency of permanent magnet motors.