Development and Analysis of Doubly Salient Brushless DC Generators for Automobile Auxiliary Power Unit Application

The doubly salient brushless dc generator (DS-BLDCG) is constituted by a doubly salient electro-magnetic generator (DSEG) and the associated rectifier circuit. Due to its merits of simplicity, high robustness, low cost, and flexible control, the DS-BLDCG is suitable for the automobile auxiliary power unit (APU) application. Since no constraint is imposed to the number of phases of the onboard brushless dc generator, the polyphase DSEG can be applied. In this paper, a 3-phase 12/8-pole DSEG and a 4-phase 16/12-pole DSEG for the APU application are proposed. The taper stator pole and broadened rotor pole structure utilized to increase maximum output power is introduced in the 4-phase DSEG design. Based on the two-dimensional finite-element method (FEM) and field-circuit coupling analysis, a comprehensive comparison is presented. The 16/12-pole DS-BLDCG exhibits better fault tolerant capability, lower voltage ripple, and higher output power, while the copper consumption of the 12/8-pole DS-BLDCG is less than the 16/12-pole one. A prototype 12/8-pole DS-BLDCG for the APU applica-tion is designed and developed. Both the simulation and experimental results indicate that the developed DS-BLDCG is a promising option for automobile APU application.