Field-Oriented Control Of 42-V Automotive Claw-Pole Synchronous Generator System Without Speed And AC Voltage Sensors

In recent years,the electrical demand in automobiles has been increasing steadily with the introduction of more and more electrical devices.However, traditional 14-V automobile power generation system,which is still widely used nowadays,is not able to meet the foreseeable future power requirements due to its inherent design limitations.A new high-power,high-efficiency 42-V claw-pole synchronous generator system,therefore,is proposed in this thesis.A PWM rectifier is directly connected to the generator,and field-oriented control principle is also introduced to ensure the DC output voltage stabilized at 42-V.The models of the claw-pole generator,the PWM rectifier and the battery are presented.The claw-pole generator is modeled based onαβcoordinates in the generating direction and two different voltage control strategies are also proposed in order to control the AC electromotive force of the generator and the DC output voltage of the rectifier.The field current loop is regulated with varying speed. Meanwhile,a double closed-loop system including phase current and DC voltage is also introduced.Among them,the phase current loop is used as inner loop,and the DC voltage loop is used as outer loop to ensure the DC output voltage stabilize at 42-V with loads changing.To reduce the cost of the system,the control system without speed and AC voltage sensors is presented.The speed of the generator and the terminal AC voltage of the generator are calculated based on the DC output voltage of the rectifier and the switching signals of the PWM rectifier.The dynamic response of the system is as the same as the system with speed and AC voltage sensors used.The proposed approaches have already been evaluated by the real-time simulation experimental results.