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In recent years sensorless techniques based on HF carrier injection have become very popular as they are capable to estimate rotor position in a wide speed range. They can provide precise control over interior PMSMs without the accompanying need for a position sensor. However, in surface-mounted PMSMs, the estimation of rotor position is only reliable at light loads due to the very small saliency arising from main flux saturation. The anisotropy caused by stator flux saturation is not necessarily in alignment with rotor position especially at heavy loads. In this paper a novel solution is proposed to make use of the sensorless scheme in a surface-mounted PMSM even at heavy loads  

Position sensorless control of ac machines at zero and low speed is possible using high-frequency carrier injection methods. These methods utilize anisotropic properties of rotor. Therefore, they may lose their efficiency for nonsalient machines or machines with small rotor saliency. In these machines, measurement noise and offset, existing delays, as well as model uncertainties may lead to inaccurate estimation of rotor position. Stator resistance which is usually neglected in these methods may also lead to a considerable error especially in machines with small rotor saliency. In this paper, a new position estimation method is presented, and it is shown that in comparison to conventional... 

High frequency (HF) carrier injection schemes can estimate rotor position in a wide speed range. In these methods, first a HF voltage is injected to stator windings and then the corresponding HF current is exploited to estimate the position of rotor using a closed loop tracking observer. The tracking observer is capable to track rotor saliency with no steady state error. However when the motor starts to move or whenever the rotor speed changes a transient error appears. In this paper a new solution is proposed to compensate the transient error in estimation of rotor position  

Sensorless schemes based on HF carrier injection are capable of estimating rotor position in a wide speed range. In these schemes first an additional HF voltage is injected to stator windings. The corresponding HF current is decoupled from main stator currents and the position of the rotor saliency is estimated based on the decoupled HF current in a closed loop tracking observer. The tracking observer is capable of tracking rotor saliency with no steady state error. Transient error appears when the motor starts to move or whenever the rotor speed changes because of any disturbance or any change in the rotor speed command. In this paper a new solution is proposed in order to compensate for... 

Control of Synchronous Motors at low speed has been the topic of several studies for the last years. Due to the lower amplitude of Back-EMF voltage in lower speed, it is inappropriate to merely rely on induced voltages for position estimation. In this paper, a new double carrier PWM modulation is presented in which two carrier frequencies are utilized for two legs of the inverter. This proposed method rectify the need of powerful processors which decreases the cost of the electric drive system. Employing a non-linear control system and an automatic gain control, ensures the sensorless control of the motor for a wide range of speed. © 2019 IEEE  

Sensorless control of permanent magnet synchronous motors allows reducing cost and complexity, and increasing mechanical robustness and noise immunity. Sensorless methods based on high frequency carrier injection have attracted considerable attention in recent years as they can estimate rotor position in a wide speed range. These methods employ anisotropic properties of rotor to estimate rotor position in ac machines. With internal permanent magnet motors, the high frequency signal injection method can deliver precise sensorless control, however in surface-mounted permanent magnet machines, where a small saliency arises from main flux saturation, the estimation of rotor magnet position is...