Research On Current Sensorless Vector Control System For Permanent Magnetic Synchronous Motor

The vigorous development of electric drive equipment is an important measure taken by countries around the world to implement energy strategy transformation. Currently one of the two major problems which need to be solved imminently is the security and reliability of the control system. As one of the main motor of electric drive systems, the safety and stability of surface mounted permanent magnet synchronous motor (SPMSM) has become one of the most attractive research fields. Of course, there are many factors which can affect the safety and reliability of the electric drive systems, such as the working environment, the structural defects of the motor itself, the control strategies and so on. Starting with the structural characteristics of commonly-used motor control strategies, this paper proposed a current estimation scheme to avoid potential security issues caused by the SPMSM vector control system which has more than one physical sensors. Finally, the current sensorless vector control of SPMSM is realized, and a series of simulation and experimental verification are carried out.Firstly this paper introduced the structural characteristics and types of permanent magnet synchronous motor, and then under the principle of coordinate transformation, the dynamic mathematical model of PMSM at different coordinates is established. According to the structural features of SVPWM and the nonlinear, strong coupling, multi-variable of the control object, then taking good advantage of the flexible and simple control theory of back-stepping, a novel adaptive back-stepping observer is presented. The designed observer can be capable of current estimation of d-q axis stator currents and resistance as the current sensors. In order to eliminate or weaken the influence of the parameters of the motor on the result of the estimation, a new deviation compensation method based on rotational electromotive force is proposed, which can improve the estimation ability and the real-time control capability of the observer.To verify the estimated performance of the observer, the simulation model of the SPMSM with current sensor and without any current sensor were built under the real-time simulation support system Matlab/Simulink, and the simulation results show that the proposed algorithm can quickly track the reference currents of d-q axis, moreover, it can ensure that the control system achieves few harmonic components in currents, good dynamic performance and strong anti-interference ability and high degree of flexibility.Finally, a SVPWM control system of SPMSM without any current sensor is built in the laboratory environment to verify the correctness of the theory and the feasibility of the system. The paper has finished the design of the peripheral hardware circuit and the corresponding software based on novel digital signal processor named DSPF28335, which capable of processing floating-point. Software program is written by C language under the CCS v5.0 integrated development environment. Besides, the paper has detailed realization of SVPWM algorithm, main regulator and the adaptive back-stepping observer. Finally, the proposed algorithm is verified by experiments, and the current sensorless vector control of SPMSM is realized. The results of the experiment are analyzed, which has important reference value for the practical application.