Sensorless torque control of salient-pole synchronous motor at zero-speed operation

Abstract

A position and speed sensorless control using the counter electromotive force of permanent-magnet motor (PM) debases the control performance at a low speed. We will propose a controllable system at full speed, including a zero speed using saliency.At low speed, the sensorless control is made by observing a current ripple at a time when alternating voltage has been applied to a salient-pole motor. Also, for discriminating the S and N poles of the magnet, magnetic saturation is used. A device has been applied to the motor rotor to allow the magnetic saturation to come about easily.Furthermore, at a time of high speed, drive at a full-speed range has been accomplished by switching smoothly over to a sensorless driving system making use of counter electromotive force. All algorithms are implemented by software, and this system can operate successively from starting to high-speed operation.Shown herein are the operational principles at a low speed, analysis and experimental results, the control scheme, how to changeover the control mode at a high speed, and the experimental results.Index Terms-Permanent-magnet motor, salient pole, sensorless drive.

Optimized High Frequency Signal Injection Based Permanent Magnet Synchronous Motor Rotor Position Estimation Applied to Washing Machines

“…• Transient signal injection based schemes which exploit the PWM signal in order to extract the rotor position or to inject discrete test voltage pulses in a defined direction (Raute et al, 2007;Belie et al, 2010;Vogelsberger et al, 2010) • Continuous high frequency signal injection based schemes which consist on injection of signal reported to a rotating high frequency voltage vector in the stator reference frame (α,β), (Perassi et al, 2005;Hu et al, 2008) or injection of signal reported to a pulsating high frequency voltage vector in a reference frame (d,q) synchronous with the motor saliency (Aihara et al, 1999;Sakamoto et al, 2001;Holtz, 2008;Wiedmann et al, 2009;Kock et al, 2009) Transient signal injection schemes are very complex to be implemented for practical real time systems whereas continuous high frequency signal injection schemes are based on a simple excitation and are easier to be experimentally implemented. However, continuous HFSI technique performance and robustness depend on the parameters choice of the high frequency signal injected in order to extract the rotor position or the rotor position error (Taniguchi et al, 2007).…”

“…As the HFSI method consists in injecting a high frequency voltage on the d-axis rotor voltage, it causes magnetic saliency excitation (Aihara et al, 1999;Sakamoto et al, 2001). Then, the HFSI results in high frequency voltage and current components and in an error rotor position ∆θ e defined as Eq.…”

High-Speed Analysis of 3-phase High Frequency Voltage Input Sensorless Control Fed by PWM Inverters Considering Magnetic Saturation

“…In the case of field-strengthening, motor reluctance increases due to magnetic saturation. Hence, we can specify the magnet polarity by measuring the increase in motor reluctance (2) (3) . From (8) and (9), following high frequency current amplitude I p is defined.…”

Improved Rotor Position Estimation in Extended Back-EMF Based Sensorless PM Brushless AC Drives with Magnetic Saliency

“…MODELING [2]- [4]. Hence, it is common to employ a hybrid a L R 0 i 1+1 dw Idt (1) sensorless technique, which uses both a signal injection based b IIs i method and a back-EMF based method [5]. Back-EMF based LvC 0 0 RS icL dVfcldt sensorless methods were first developed to estimate the rotor where va, vb, vc ia, ib, ic, V1a, Vib and are the 3-phase voltages, position of BLAC motors having a surface-mounted PM rotor currents, and flux-linkages, respectively, and Rs is the phase without rotor magnetic saliency.…”

“…back-EMF based sensorless schemes [2]- [5]. The modeling of Clearly, qI/d, fqi dqdid/t and dfqiqdt vary non-linearly with the dq-axis cross-coupling magnetic saturation, the investigation of d-and q-axis currents, due to the influence of magnetic its influence on the accuracy of the rotor position estimation in saturation.…”