Brushless direct current motors with permanent magnets for marine electric drive systems: state and prospects

Abstract

The main trends in the development of designs, power semiconductor circuits and control systems of promising valve electromechanical converters — brushless DC motors with permanent magnets for marine electric drive and automation equipment, are discussed in the paper. A variant of their implementation in an adjustable electric drive is presented. The object of the study is a brushless direct current electromechanical system, including a synchronous machine with magnetoelectric excitation, covered by positional feedback through a dependent controlled valve switch, and the subject is structures, the circuit of the power part, control systems, the algorithm of functioning and characteristics. The purpose of the research is to evaluate the operational features, properties and possibilities of introducing brushless direct current motors with permanent magnets as marine electric drive systems of low and medium power. The results of research and development are embodied in experimental industrial samples. A variant with microprocessor control has been developed for marine electric drive systems. The switch is assembled on transistor switches that provide high reliability and enhance the functionality of the control system. The minimum necessary system of logical variables, ensuring the implementation of rational laws of switching and speed control, has been formed. Operational characteristics at various leading angles of switching on the switch valves are presented. The presence of pole shoes at the poles introduces significant features in the patterns of their change. The main advantages and features of the proposed design and circuit solutions are formulated in the conclusions. It is indicated that valve motors with excitation from permanent magnets are the most promising solution in terms of integrating an electromechanical converter into an adjustable marine electric drive of a range of small and medium capacities.Engines of this type are structurally simple and reliable, have rigid natural mechanical characteristics, do not require energy for excitation, have a large overload capacity and high speed in transients. Their distinctive feature is the high specific moment.