Speed Sensorless Control Based on Virtual Secondary Vector Superposition Method for Segmented Parallel-connected Long Primary Double-sided Linear Induction Motor

The segmented parallel-connected long primary double-sided linear induction motor (LPDSLIM) driven by multi-inverter, due to its time-varying parameter characteristics, causes the existing speed sensorless control methods incompatible. In response to this issue, a novel speed-sensorless control strategy that integrates the virtual secondary vector superposition(VSVS) equivalent model with second-order super-twisting sliding mode theory is proposed in this article. Firstly, the mathematical model of LPDSLIM is analyzed. An equivalent mathematical model is established based on VSVS, which simplifies the complex segmented motor mathematical model into a topologically isomorphic mathematical model relative to rotary induction motors. Secondly, a second-order super-twisting secondary flux linkage observer is designed based on this model, utilizing a higher-order sliding mode structure to enhance estimation of secondary flux linkage dynamic response speed. Finally, the simulation results verify the proposed method.