Sensorless Control of Dual Three-Phase IPMSM Based on Frequency Adaptive Linear Extended State Observer

The sensorless control of interior permanent magnet synchronous motor based on the conventional linear extended state observer (LESO) does not have sufficient capability to eliminate the steady-state position estimation error. To solve this issue, a frequency adaptive LESO (FA-LESO) is proposed to estimate the back electromotive force accurately. The gains of the proposed observer are designed according to the pre-designed transfer function of a second-order complex-coefficient filter, whose stability is guaranteed by the generalized Routh criterion. The linearized model of the proposed FA-LESO is established and the design guideline of the observer gains is presented. Compared with the conventional LESO, the proposed FA-LESO can eliminate the steady-state position estimation error without any phase compensation. Meanwhile, it exhibits better high-frequency noise immunity without additional filters being required. The feasibility and effectiveness of the proposed FA-LESO are verified by the comparative experiments on a dual three-phase IPMSM platform.