Study On The Integrated Starter/Generator And Its Control System For Autos

With the continuous development of the automotive industry, the problems ofresources and environment become threaten to the earth and people’s daily lives. It islikely to be the world of the electric vehicles and in the interim, hybrid cars wouldhave come into being. The most core technology of hybrid cars is integratedstarter/generator technology. Instead of starting and generating by two motor, theessence of this integrated starter/generator technology is that there is only one motor,which can reach the purpose of one machine owning two effects and time divisionmultiplexing. Once more, it can improve efficiency, save fuel and reduce emissions,which have a very important practical meaning on the environment and people’slivelihood.At the beginning of this paper, there is an introduction about the development ofintegrated starter/generator technology and related technologies, which points out thedirection for the later research and contributes to selecting the permanent magnetsynchronous motor as the integrated starter/generator body.Then this article designs the rotor structure, the stator winding of the integratedstarter/generator motor. At the same time it designs an appropriate electromagneticload after studying the impact of the electromagnetic load on the motor performance,which definitely could meet the requirements of a better performance, high powerdensity and matching PWM Rectifier. Next, it tries to verify the reasonableness of thedesign parameters of the motor by simulating with ANSOFT and no-loadelectromotive force measurement experiment.After this, the paper mainly studies the entire control system of integratedstarter/generator machine divided into two states, motor-driven and power generationmodes. There are different control objectives and strategies corresponding to differentmodes: in motor-driven mode, to make the motor smoothly and start fast, it can useSVPWM vector control strategies. While in the generating mode, the main task is torectify the output voltage of generator for the purpose of providing electrical power tothe vehicle equipment and battery. Since Vehicle equipment are turned on and offusually and sometimes would cause load mutation, the rectification strategy shouldown strong anti-disturbance performance. Because of large current of integratedstarter/generator causing inductor saturation possibly and affecting the control effect,this article introduces a new dual closed-loop rectifier strategy. Taking economic efficiency into consideration, this article uses the MOSFET parallel connectionmethod to construct rectifier and inverter device for the MOSFET’S advances of fastswitching speed and small power consumption. When MOSFETS are connected inparallel, current sharing and switching time consistency should be considered.So inthe actual hardware design process, the measures, such as, resistance be connected atgate, radiating device be added and wires be arranged reasonably, can be took.Finally, as a platform, the MATLAB/SIMULINK model each module and setsparameters completing individual control of the motor-driven, power generation stateand switching control occurred in the moment when motor reaches the ignition speed.Moreover it verifies the feasibility of new double closed-loop control strategy.After the analysis of the first few chapters, based on the DSP chip, the relatedperipheral circuits are designed, such as MOSFET driver, position&speed detectingcircuit and the DSP serial communications interfaces, etc. Finally it completes thebench test and gives experimental results.