Output Delay Sliding Mode Tracking Control of SRM based on Multi-innovation Model Identification

Abstract

The drive system of switched reluctance motor (SRM) is a complex nonlinear system that is composed of many links. The delay in the measurement of the speed and position signal of SRM is caused by the factors that affect the measuring sensor. To effectively improve the influence of the SRM rotor position and speed signal delay on the system performance, a sliding mode position tracking method based on output delay observation was proposed in this study. First, the model was discretized according to the structure and characteristics of SRM and the mathematical parameters of the system were identified using a multi-innovation stochastic gradient (MISG) algorithm. Second, a delay state observer was constructed on the basis of an SRM system model with output delay. Then, the sliding mode tracking control method based on the delay state observation compensation was proposed and combined with sliding mode control theory. Lastly, the effectiveness of the designed model parameter identification, delay state observation, and output delay control methods were compared through numerical simulation. Results show that when uncertain factors, such as noise, are present in the system, the MISG identification method can rapidly and accurately identify the parameters of the SRM model compared with the stochastic gradient identification method; the identification accuracy of the former is four times higher than that of the latter. Similarly, the sliding mode position tracking control method based on output delay observer can rapidly and accurately track the position and speed within 0.5 s. However, its position (0.2 rad) and velocity (0.233 rad/s) tracking exhibit large steady-state errors when no delay observation compensation is present. The proposed method not only demonstrates high position tracking accuracy, but also possesses strong robustness to output delay.