Modelling a laminated brushless exciter-alternator unit in all modes of operation

The brushless exciter is now widely used in alternator excitation systems as it offers the advantage of reduced maintenance. An accurate modelling of the exciter-alternator set is important for design and operation engineers. An accurate detailed model of the set is presented. The exciter is modelled as a synchronous machine in the direct phase reference frame, to comply with the nature of the rectifier circuit. Kron´s tensor method for analysis of electrical circuits is utilised, and a variable connection matrix is developed to suit the variable topology of the exciter circuit. A complete mathematical model that covers all the modes of operation of the rotating bridge rectifier circuit is developed. Short circuit transient results are computed and compared with test results