The Research Of Sensorless Vector Control On Motor In Hybrid Vehicle

The rising oil prices and environmental problems are affecting the development of the entire automotive industry.These factors also drive the automotive industry toward a more efficient and environmentally friendly approach.The current trend of develop-ment shows that oil is being marginalized,and the use of electricity as a vehicle power gradually becomes the future direction of the development for automobiles.As a tran-sition stage vehicle,hybrid electric vehicle has the characteristics of zero emission and low pollution,and has won public recognition.PMSM has been widely used in hybrid vehicles because of its excellent power density,high efficiency,high torque and low inertia.In the closed-loop control of PMSM vector control and direct torque control,the rotor position and speed are re-quired to be detected.The traditional way to obtain the rotor position angle information is to use an encoder or a resolver.However,in the hybrid vehicle driving mechanical sensor in the motor,the rotor shaft vibration,and often work in harsh environment,thus the system reliability can not be effectively guaranteed,at the same time,the use of the position sensors increases the system volume.The application of sensorless con-trol technology of PMSM eliminates the mechanical position sensor and effectively overcomes the defects of mechanical sensors.However,the existing sensorless control techniques have limitations of applicable speed range.In order to realize sensorless control in full speed range,sensorless control technology with different range of appli-cations should be combined.In this paper,the IPMSM in hybrid electric vehicle is studied,and sensorless con-trol in full speed range is studied in detail.After the motor model of PMSM in three phase stationary coordinate system is deduced,the motor equations in two phase rotat-ing coordinate system and two phase stationary coordinate system are obtained by coordinate transformation.On this basis,the vector control scheme of PMSM is stu-died.The basic principle of high frequency signal injection method and effective flux observer method are introduced in detail.They are applied to PMSM low speed and middle high speed sections respectively.The whole range sensorless control is carried out by combining the method used in the high-speed range and the high frequency signal injection method used in the low speed range.Among them,the weighted me-thod is used to guarantee the smooth switching of different control methods at low speed,medium speed and high speed.At the end of this paper,the PMSM is simulated and verified by the compound control method proposed in this paper.The results show that the composite control method of this type proposed can reliably estimate rotor po-sition and speed in full speed range.