Description and Analysis of Switched Mode Chopper Amplifier for DC Attraction Type Levitation System

Power amplifier plays most important part of the electromagnetic suspension system. The advances in the technology of attraction type magnetic levitation are attributable almost entirely to the development of solid state electronic and power semiconductor devices. The amplifier should have properties like fast dynamics, wide bandwidth, ability to handle large payload, energy efficient, high reliability and should be cost-effective. Both linear and switching mode power amplifiers have been used in the field of DC electromagnetic suspension system. In this paper different possible switched mode power circuits for single magnet based electromagnetic levitation system have been discussed and a comparative study has been made of the different topologies of power amplifiers based on their structure and some experimental results. In the actual work design, fabrication and testing of an electromagnetic levitation scheme has been made as a complete project. But in this paper the emphasis is given on power amplifier portion due to limitation of space. A new single switch based switched mode power amplifier for electromagnetic levitation has been introduced. This circuit is simpler in topology and has some definite advantages over mostly reported asymmetrical H-bridge converter (N.A. Shirazee and A. Basak, 1995).