Adaptive Speed Sensorless Permanent Magnet Synchronous Motor Control Method

Because of the existence of mechanical sensor in the permanent magnet synchronous motor drive system, it doesn't only increase the motor shaft rotational inertia, the volume and cost of motor, but also decrease the system robustness and reliability. Therefore it has caused a lot of attentions to permanent magnet synchronous motor speed sensorless control techniques. Stator resistance along with outside time-variable has the enormous influence to the speed identification, which can lead to the instability of observer, so speed sensorless control technology which eliminate the influence of stator resistance uncertainty become the hot spot of research.This paper presents a new speed identification method based on Lyapunov in the permanent magnet synchronous motor vector control system. In this method, it uses the mathematical model of permanent magnet synchronous motor ontology as reference model, construct the adaptive observer which uses the stator flux and stator current as the state variables, deduce the speed identification rate on the basis of the stability of observer. At last the simulation results verify the effectiveness of the proposed method, by the comparative analysis with Popov simulation results it shows that the method presented in this paper has a better speed identification effect, dynamic and static performance, and good robustness.Aiming at the system stability is influenced by the state resistance uncertainty along with the outside, this paper proposes two kinds of new improvement speed identification method which base on the robust adaptation.The first kind is based on two stability theory speed identification method, this method regards the stator resistance as the time-variable quantity and deduces the speed adaptive law based on the Lyapunov stable theory which guarantees the system stability. The second is model reference adaptive speed identification program based on a new stator resistance robust observer. This method re-design an adaptive observer and the time variable of stator resistance is seen as robustness. Under the premise of stability theory to guarantee system stability, the stator resistance robustness and speed adaptive laws are derived. By MATLAB simulation to analysis the two experiments, the results show that the two programs can eliminate influence of stator resistance changes for speed identification, the first is complex in theroy and the algorithm is simple and the simulation is ideal. In the second program, the algorithm is complex and the caculation is large, but the simulation is better.