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In low-speed sensorless control of surface-mounted permanent magnet synchronous machine (SPMSM), high-frequency (HF) signal injection methods are often used to estimate the rotor position by tracking the motor saliency characterized by the inductances. Cross-saturation effects caused by the load current will influence the inductances, and consequently the saliency, which will introduce position estimation error to the sensorless drive, degrading the drive performance. Such load-dependent position estimation error, which is inherent in HF signal injection sensorless methods, is difficult to be identified by the sensorless algorithm itself. This article proposes a new online method to detect and compensate the load-dependent position estimation error for SPMSM without additional devices or the knowledge of the load-dependent HF inductances. The proposed method can identify effectively the load-dependent position estimation error by simply varying the direction of the current vector. Experimental results are presented to validate the proposed solution. [ABSTRACT FROM AUTHOR]

This paper presents a sensorless-controlled, low-cost, low-power, and variable-speed drive system suitable for fan and pump applications. The main advantages of this drive system are the low system cost, simple converter structure, and simple but robust sensorless control technique. The drive motor is a special hybrid switched reluctance motor. The proposed sensorless control method beneficially utilizes the stator side PM field and its performance is motor parameter independent. The unique low-cost drive system solution, simple and robust sensorless control features of this drive system, is demonstrated in detail in this paper. Important design details for practical implementation of the sensorless control algorithm are included. The complete drive system performance is validated using a prototype drive system. [ABSTRACT FROM AUTHOR]

This paper presents a new low-cost hybrid switched reluctance (HSR) motor intended for use in adjustable-speed pump drive systems. The motor is a single-phase motor, driven by a unipolar converter, which uses both the reluctance torque and the permanent magnet interaction torque. Compared with conventional single-phase switched reluctance motors, it has an increased torque density. The cogging torque is beneficially used in this motor for reducing the torque ripple. It is demonstrated that such a motor drive system can be a suitable candidate to advantageously compete with the existing motor drive systems for low-cost applications. Finite-element models are used to analyze and predict the motor's performance. The proposed motor drive system has been fabricated, and its performance has been tested in the laboratory. These experimental results are also presented. [ABSTRACT FROM AUTHOR]