Research On Control Strategy Of A New On-board Generation System Using Doubly Salient Brushless DC Generator

The on-board generation system of electric vehicles, which resolves the problem that pureelectric vehicles are of short driving range, is of great importance for the development of new energyvehicles. Doubly salient brushless DC generator is with simple construction, reliable operation, andflexible control. Thus, a new on-board generation system with doubly salient brushless DC generatoris presented in this paper. Its operation principle, control strategy and output characteristics areinvestigated.The requirements for system structure, operation principle, and operation models of on-boardgeneration system in different hybrid electric vehicles are summarized systematically. The structure ofgeneration system and vehicle powertrain system in extended range electric vehicle (EREV) is stated.The power coordination relationships among generation system, battery system and driving system indifferent traffic conditions are analyzed. Based on the analyses of the power coordinationrelationships, control strategy of range extender, which is known as constant voltage control&constant current control&constant power control, is discussed.The operation principle and electromagnetic characteristic of double salient electro-magneticgenerator (DSEG) is discussed, and the influence of doubly excitation windings to outputperformance is studied. Hardware and software of the generator digital control unit is designed, toachieve the functions of power regulation¤t regulation control strategy, fault protection,communication and so on.A prototype machine of45kW doubly salient brushless DC on-board generation system isdeveloped, so as the experimental bench. The experimental results validate that the generation systemis of simple and reliable structure, and flexible control strategy. And it could operate well in constantvoltage control, constant current regulation and constant power regulation mode with resistance andbattery loads. The experimental result verifies that the new on-board generation system is of importantvalue for research and application in powertrain system of new energy vehicles.