Direct Thrust Force Linear Control Methods for Linear Flux Switching Permanent Magnet Motor based on Space Vector Modulation

Linear flux switching permanent magnet (LFSPM) motors show significant potential in many applications from urban rail transit, automobile to naval. Direct force control (DFC) methods are always employed for the linear motor driven systems owing to their high dynamic performance and parameter robustness. However, the traditional DFC has the drawbacks of big ripples and nonlinear hysteresis control for both thrust force and primary flux linkage. Two direct force linear control (DFLC) methods based on space vector modulation (SVM), namely, DFLC-SVM1 and DFLC-SVM2, are presented in this paper, where the hysteresis controllers are removed, and the relationship between the electromagnetic force and the thrust angle or its increment is established. Thus, an accurate and linear control of the electromagnetic force can be achieved through SVM. Furthermore, DSLC-SVM2 is simpler than DSLC-SVM1 due to that it does not require electromagnetic force estimation part, only the primary flux estimation is needed. Simulation results verifies the effectiveness of the two methods.