Position estimation for PMSMs at any speed using the zero-sequence voltage and modified space vector modulation

Anisotropy-based estimation techniques enable position and speed estimation for synchronous and induction machines down to low speeds and standstill. One possible approach consists of exciting the machine with special pulse patterns and measuring the zero-sequence voltage which requires access to the neutral point of a star-connected machine but can in return enable high signal-to-noise ratios. This thesis focuses in particular on permanent magnet synchronous machines and aims to contribute to the understanding of fundamental relations through a mathematical analysis of the underlying anisotropy information as well as to practical aspects that include initial polarity detection, usable pulse patterns and investigations on certain non-ideal effects which real machines exhibit. Experimentally achieved estimation results using real machines are presented, which demonstrate in particular low noise content and little dependence on rotor speed.Anisotropiebasierte Schätzverfahren ermöglichen Positions- und Drehzahlschätzung für Synchron- und Induktionsmaschinen bis hin zu niedrigen Drehzahlen und Stillstand. Ein möglicher Ansatz besteht darin, die Maschine mit speziellen Pulsmustern anzuregen und die Nullspannung zu messen, was den Zugang zum Sternpunkt einer im Stern verschalteten Maschine erfordert, dafür aber hohe Signal-Rausch-Verhältnisse ermöglichen kann. Diese Arbeit konzentriert sich insbesondere auf Permanentmagnet-Synchronmaschinen und möchte durch eine mathematische Analyse der zugrundeliegenden Anisotropie-Information zum Verständnis grundlegender Zusammenhänge beitragen sowie zu praktischen Aspekten, darunter die Erkennung der anfänglichen Polarität, verwendbare Pulsmuster und Untersuchungen zu bestimmten nicht-idealen Effekten, welche bei realen Maschinen auftreten. Es werden experimentell erzielte Ergebnisse der Schätzung bei realen Maschinen vorgestellt, die insbesondere einen geringen Rauschanteil und eine geringe Abhängigkeit von der Rotordrehzahl aufzeigen

Speed -Sensorless Estimation And Position Control Of Induction Motors For Motion Control Applications

Thesis (Ph.D.) University of Alaska Fairbanks, 2006High performance sensorless position control of induction motors (IMs) calls for estimation and control schemes which offer solutions to parameter uncertainties as well as to difficulties involved with accurate flux and velocity estimation at very low and zero speed. In this thesis, novel control and estimation methods have been developed to address these challenges. The proposed estimation algorithms are designed to minimize estimation error in both transient and steady-state over a wide velocity range, including very low and persistent zero speed operation. To this aim, initially single Extended Kalman Filter (EKF) algorithms are designed to estimate the flux, load torque, and velocity, as well as the rotor, Rr' or stator, Rs resistances. The temperature and frequency related variations of these parameters are well-known challenges in the estimation and control of IMs, and are subject to ongoing research. To further improve estimation and control performance in this thesis, a novel EKF approach is also developed which can achieve the simultaneous estimation of R r' and Rs for the first time in the sensorless IM control literature. The so-called Switching and Braided EKF algorithms are tested through experiments conducted under challenging parameter variations over a wide speed range, including under persistent operation at zero speed. Finally, in this thesis, a sensorless position control method is also designed using a new sliding mode controller (SMC) with reduced chattering. The results obtained with the proposed control and estimation schemes appear to be very compatible and many times superior to existing literature results for sensorless control of IMs in the very low and zero speed range. The developed estimation and control schemes could also be used with a variety of the sensorless speed and position control applications, which are challenged by a high number of parameter uncertainties

Induction Motors

AC motors play a major role in modern industrial applications. Squirrel-cage induction motors (SCIMs) are probably the most frequently used when compared to other AC motors because of their low cost, ruggedness, and low maintenance. The material presented in this book is organized into four sections, covering the applications and structural properties of induction motors (IMs), fault detection and diagnostics, control strategies, and the more recently developed topology based on the multiphase (more than three phases) induction motors. This material should be of specific interest to engineers and researchers who are engaged in the modeling, design, and implementation of control algorithms applied to induction motors and, more generally, to readers broadly interested in nonlinear control, health condition monitoring, and fault diagnosis

Predictive current control in electrical drives: an illustrated review with case examples using a five-phase induction motor drive with distributed windings

The industrial application of electric machines in variable-speed drives has grown in the last decades thanks to the development of microprocessors and power converters. Although three-phase machines constitute the most common case, the interest of the research community has been recently focused on machines with more than three phases, known as multiphase machines. The principal reason lies in the exploitation of their advantages like reliability, better current distribution among phases or lower current harmonic production in the power converter than conventional three-phase ones, to name a few. Nevertheless, multiphase drives applications require the development of complex controllers to regulate the torque (or speed) and flux of the machine. In this regard, predictive current controllers have recently appeared as a viable alternative due to an easy formulation and a high flexibility to incorporate different control objectives. It is found however that these controllers face some peculiarities and limitations in their use that require attention. This work attempts to tackle the predictive current control technique as a viable alternative for the regulation of multiphase drives, paying special attention to the development of the control technique and the discussion of the benefits and limitations. Case examples with experimental results in a symmetrical five-phase induction machine with distributed windings in motoring mode of operation are used to this end