Permanent Magnet Synchronous Motors are Globally Asymptotically Stabilizable with PI Current Control

This note shows that the industry standard desired equilibrium for permanent magnet synchronous motors (i.e., maximum torque per Ampere) can be globally asymptotically stabilized with a PI control around the current errors, provided some viscous friction (possibly small) is present in the rotor dynamics and the proportional gain of the PI is suitably chosen. Instrumental to establish this surprising result is the proof that the map from voltages to currents of the incremental model of the motor satisfies some passivity properties. The analysis relies on basic Lyapunov theory making the result available to a wide audience

Comprehensive high speed automotive SM-PMSM torque control stability analysis including novel control approach

Permanent magnet synchronous machines (PMSM) are widely used in the automotive industry for electric vehicle (EV) and hybrid electric vehicle (HEV) propulsion systems, where the trend is to achieve high mechanical speeds. High speeds inevitably imply high current electrical frequencies, which can lead to a lack of controllability when using field oriented control (FOC) due to sampling period constraints. In this work, a comprehensive discrete-time model is fully developed to assess the stability issues in the widely used FOC. A speed-adaptive control structure that overcomes these stability problems and extends the speed operation range of the PMSM is presented. Also, a numerical methodology from which the maximum operating stable frequency can be computed in advance of any experimentation, is developed. All contributions are accompanied and supported by numerical results obtained from an accurate MATLAB/Simulink model.Peer ReviewedPostprint (published version

Design of second order sliding mode observer based equivalent Back-EMF for rotor position estimation of PMSM

This study introduces a scheme to estimate rotor position by the use of an Equal electromotive force (EMF) model of a synchronous machine. This use could be substituted by a sliding-mode observer (SMO) according to an equal EMF for superior reference speed tracking. There is an algorithm of the second order sliding-mode-control (SO-SMC) in controlling speed of permanent magnet synchronous motor (PMSM). This is by the use of the proportional plus-integral PI control sliding plane. The current work discusses the PMSM, which follows field-oriented appears. In addition, there are SO-SMC laws and PI sliding plans. This paper shows that the proposed high-speed PMSM sensorless speed control is valid by MATLAB simulations

Magnetic Guidance for Linear Drives

Linear drives provide many new attractive solutions for the material transportation and processing in the manufacturing industry. With no mechanical transmission elements, they enable high dynamics and rigidity as well as low installation- and low maintenance-costs. That performance can give the linear motor system a better precision, a higher acceleration and a higher speed of the moving part. Therefore, the material transportation and processing using linear motors is studied and applied increasingly in manufacturing industry. For these applications, the linear motor is typically with stationary long primary and a short moving secondary. As the secondary part is passive, no energy transmission is required between the moving and stationary part, avoiding the use of brushes or inductive transmission. The motor type best suited for the mentioned applications is the synchronous one with permanent magnets, because of its higher efficiency, compactness, but most important because it allows a higher air-gap. In the usual approach, the linear motor is only used for thrust force production. The guidance is usually implemented by a mechanical assembly. The guidance constrains the movement to the longitudinal displacement, fixing the lateral and vertical displacement: yaw, roll and pitch. To achieve the necessary precision of the movement, accurate mechanical guidance is required. Such the mechanical assembly can be complex and source of high friction. In this dissertation, a research of an active guiding system is presented. The purpose of this research is finding out a solution for the material transportation and processing applications. The target is a linear drive system, which can reduce the complicated mechanical structure. In additions, the passive vehicle is also necessary. The result of the research is PM-synchronous linear motors with long and double-sided primaries. In the system, the lateral displacement and the yaw angle are controlled while a simple wheel-rail system fixes the vertical displacement. This combination of the magnetic and mechanical guidance offers a good trade-off among the complexity of the control, actuators and mechanics, when considering industrial applications. To allow multiple vehicles traveling simultaneously and independently on the guide-way (each vehicle is controlled by an individual part of the guide-way), the double side primary is separated into segments. With that structure, flexible-operating methods can be implemented. That is very useful in process-integrated material handling where different speeds of material carriers in each processing station are necessary. Another advantage of segmented structure is the energy saving. The power is supplied only to the segment or the two consecutive segments in which the vehicle runs over. In one segment, each side of the primary is supplied by its own inverter, allowing the necessary degree of freedom to control the lateral position and the yaw angle in addition to the thrust control. In order to make the vehicle completely passive, a capacitive sensor is proposed and implemented to measure the lateral position and the yaw angle. The sensor has active parts installed on the guide-way and passive parts on the vehicle. The mathematical analysis and the finite element method (FEM) are used to analysis the proposed system. With the analysed results, the control for the system is investigated in detail. Hardware and software for the experimental system is developed and implemented. The analysed results and the experimental results validate the proposed system. That gives a new solution for the material transportation and processing application using linear synchronous motors