Research On The Speed Sensorless Vector Control Of PMSM

Permanent magnet synchronous motor (PMSM) has attracted more and more attention in industry because of its excellent performances-light weight, small size, high efficiency and energy saving. With the maturity of control technology, it is playing a increasingly important role in the frequency control system for small and medium power induction motor. In PMSM control system, the precise information of the rotor position and speed is essential, which can be measured directly by mechanical position sensors. However, some defects are caused by the installation of mechanical sensors such as increasing the size and cost of the system, and it cannot guarantee its accuracy in some harsh environment so that the reliability of the system is reduced. In order to solve the problem, the sensorless control technology is proposed and became a hot research. This dissertation will target to interior permanent magnet synchronous motor(IPMSM) and the details are illustrated as followings:First of all, the dissertation introduces the mathematical model of IPMSM and the basic theories of the two vector control strategies,id=0 and maximum torque per ampere(MTPA), the latter one is more suitable for IPMSM. Based on it, quoted a predictive current control(PCC) strategy and analyzed inductance’s parameter sensitivity for it. Then introduced appropriate robust factors to improve system stability.Secondly, combined with PCC, the pulsating high frequency signal injection method is quoted in the system which is applicable to low speed control. Then detected the initial rotor position and pole polarity according to the strategy’s theory and the nonlinear saturation characteristics of the stator inductance. Then, using the disposal of quantity standard for rotor position signal and assigning pole with feedback matrix to improve the performance of rotor position observer. Then, extracted quadrature-direct axis current’s phase with PLL to obtain the more precise modulation signal and added on compensation unit to dilute the influence of delay angle and speed increase for the further optimization of observer.Model reference adaptive system(MRAS) is quoted which is applicable to high speed control. Take IPMSM as reference model and its current equation as adaptive model to build up MRAS. Then, designed the rotor speed adaptive rule based on Popov hyperstability theory. For the smooth switch between the two strategies, quoted weighted hysteresis method to make up complex observer and realized the control without speed sensor in wide speed range. The simulation results on Matlab/simulink demonstrated the correctness and effectiveness of the strategies in this dissertation.The last but not the least, the hardware-in-loop experiment platform based on RT-LAB real-time simulator and TMS320F2812 DSP controller is established, and based on it controlled object modeling and programming are completed, and the related experiment of the strategies in this dissertation is finished based on the experiment platform. The experimental results demonstrated the correctness and effectiveness of the strategies.