| Wound field doubly salient brushless dc machine is developed on the basis of doubly salient permanent-magnet machine but with field winding instead of permant magnets. Due to the simple structure with no winding or permanent magnet on the rotor, it is much more reliable and cheaper. In motoring mode, it is very easy to control due to the variable control parameters. Hence, it has a wide application prospect in the field of harsh and high-speed environment.This paper first introduces the basic structure, operation principle and mathematical model. Then, a comparison of two doubly salient structured machine with stator field winding is performed with finite element method based on simulation. Besides, according to angle divisions based on operating states of WFDS-BLDCM, this thesis proposed a novel three-phase nine-state control strategy.Then, the WFDS-BLDCM propulsion system model using three-phase nine-state control strategy is stablished by co-simulation of Ansoft Maxwell and Simplorer. Then a detailed analysis of the influence of the phase current, output torque under different control strategies is given. The different field excitation current and control angle a b is also dicussed. Due to the three phase conduction phenomenon at the same time when take three-phase nine-state control strategy, this paper propose a segmented PWM control mode, and simulation results confirms that the dynamic performance of the proposed control mode is better.At the same time, the digital controller of the WFDS-BLDCM is set up based on ARM and CPLD, and the design of software and hardware is presented. Moreover, a new position sensor according to position sensor voltage deviation is designed in order to verify the reliability.In the end, three-phase nine-state control strategy of this thesis is verified and compared with original strategies through experiments. The results shows that the proposed control strategy can effectively improve the output torque performance and efficiency. |
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