Design and simulation of a novel brushless Doubly-Fed Alternator for the pulse Capacitor Charge Power Supply

This paper presents a new type Brushless Doubly-fed Alternator (BDFA) based on the differential mode and conducts research on its application in a pulse Capacitor Charge Power Supply (CCPS). Because there are no brushes, the Brushless Doubly-fed Alternator will have high reliability and long service life. The excitation winding of the BDFA which is set on stator can be supplied with either Direct Current or Alternating Current. In previous studies, regardless of the rotor configuration, the natural speed of BDFA is 60f / (p1+ p2), i.e. based on the additive mode. In order to increase the alternator´s natural speed, expand the operating and control range and promote the alternator´s power density, this paper presents the differential mode, i.e. its natural speed is 60f /|p1-p2|. We will introduce the detailed design method of BDFA based on the differential mode. Utilizing the finite element model of the alternator, we will analyze the magnetic field distribution and calculate inductance parameters of the BDFA, and then the inductance mathematic model of the BDFA will be established. We also establish the simulation model of the pulse CCPS. Finally, we will verify the feasibility of design scheme for the BDFA through the simulation results in a pulse CCPS system. Index Terms: Brushless Doubly-Fed Alternator (BDFA); Differential Mode; Finite Element; Capacitor Charge Power Supply (CCPS).