Signal Injection Sensorless Control Without Manipulating Convergence Point Based on Symmetrical Auxiliary Angles for Saturated Synchronous Machine

This article proposes the high-frequency (HF) signal injection sensorless control (SISC) without manipulating the convergence point based on symmetrical auxiliary angles for saturated synchronous machines. The HF current signal of the existing SISC is analyzed in this article, and it is revealed that the HF current signal depends on the dynamic inductances and the angle differences between the actual rotor angle and each auxiliary angle. The proposed method can extract the pure position error signal without any compensation using an appropriate angle difference, where the angle difference depends on dynamic inductances. Compared to the existing methods, which require FEA, pre-test, and offline calculation for an accurate angle estimation, the proposed method only requires dynamic inductances. So, the proposed method can be implemented without a position sensor or rotor-locking devices, expanding the SISC applications. The magnetic flux saturation model-based implementation strategy for the plug-and-play of the SISC is also described in this article. The proposed method was verified on a 1.5 kW SynRM and an 11 kW IPMSM, and the results proved the effectiveness of the proposed method.