Research On Starting And Generating Technology Of Permanent Magnet Motor Based On Bidirectional Converter

With the development of power electronics and new motors, starter/generator system isreceiving more and more attention in the aerospace, automotive and other fields. The fundamental ofthe starter/generator system is based on the reversibility principle of motor. When start, the motorwork in electric mode; after the engine is switched to the prime mover, the motor as a generator. If weapply the starter/generator in the micro-engine system, which can’t self-start, it can reduce themachine load and improve system stability, which has significance.Firstly this paper described the research status of starter/generator system, we select thebrushless DC motor and the voltage source converter with regulator modules for study. The converterhas simple structure, and is easy to control. Meanwhile, in order to solve the problems caused byposition sensor, this paper introduces back-EMF zero crossing detection which can get the motor rotorposition signals. As for control, when start we adapt the Buck+three-phase inverter control mode;when generate, the converter works as uncontrolled rectifier bridge+Boost converter mode.Then this paper designed circuit parameters of the system, and completed simulation based onMatlab/Simulink software platform, results show that the circuit works and design are accurate. Thesimulation on back-EMF zero crossing detection and the whole system indicate that the zero crossingcircuit can effectively detect the rotor position signal, and the whole system can work smoothly.Next we introduced the software/hardware design of the system. In hardware section introducesthe structure of the main circuit system, the sampling circuit, protection circuit, position detectioncircuit, digital control systems and other parts. Software design gives control of the overall block andstart running diagram, including there main functions and implementation.Finally, this article established the actual circuit based on digital control chip of dsPIC30F3011,and completed the related experimental. We first verified the reliability of the bidirectional DC-DCconverter, and the output voltage can be stabilized at the reference value with the closed loop. Thenwe completed the experiment of generation based on the platform of high speed motor, the experimentverified that the high-frequency three-phase AC voltage emitted can be regulated to28.5V, while thevoltage ripple far below the indicator.