EPE Journal Volume 13-3 
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EPE Journal Volume 13-3 - Editorial
EPE Journal Volume 13-3 - Papers
EPE Journal Volume 13-3 - Products and Applications



 EPE Journal Volume 13-3 - Editorial 

Another special issue of EPE Journal  [Details]
By B. Sneyers

The Editorial of the EPE Journal Volume 13 N°3, "Another special issue of EPE Journal", written by Brigitte Sneyers, the Secretary General of EPE Association.


 EPE Journal Volume 13-3 - Papers 

A Study of Sensorless Control of Induction Motor at Zero Speed Utilizing High Frequency Voltage Injection  [Details]
By D. Drevensek; D. Zarko; T. Lipo

A detailed investigation of sensorless control of induction motor at zero and very low speed based on injection of a pulsating high frequency voltage signal is presented. A sensing technique is based on the secondary effect of magnetic spatial non-linearity caused by saturation of the stator laminations. Experimental and finite element results are presented.

Sensorless Rotor Position Control in a Surface Mounted PM Machine Using HF Rotating Injection  [Details]
By C. Silva; G. M. Asher; M. Sumner; K.J. Bradley

This paper presents the use of hf voltage signal injection for tracking position in an off-the-shelf surface mounted permanent magnet machine. The inherent low saliency of this type of machines presents difficulties and makes the signal conditioning highly critical. In this paper the method of space-modulation profiling (SMP) is used to obtain a magnetic signature of the machine in order to correct for periodic errors in the position signals. Experimental results illustrate the effectiveness of this technique in providing position signals of high quality. These are then exploited to provide closed loop sensorless position control of good bandwidth.

Sensorless INFORM-Control of Permanent Magnet Synchronous Machines  [Details]
By Th. Preusser

In comparison to well-known sensorless control schemes, the INFORM® method allows closed loop torque-, speed- and position-control of permanent magnet synchronous motors in the whole speed range downto standstill. This paper will look at some control schemes that have been in use for years. It will then explain the technology used for INFORM, making use of a varying reluctance around the perimeter of the machine to evaluate the rotor position. The advantages and limitations of that innovative control scheme will be pointed out and some experiences of industrial applications will be presented. The paper concludes with a lookout on further developments.

Statistic Properties of the INFORM-Method in Highly Dynamic Sensorless PM Motor Control Applications Down to Standstill  [Details]
By M. Schrödl

Industrial sensorless permanent magnet synchronous motors (PSM) working at minimum speed of about 10 % of rated speed have been in use for some years. However, PSM drives with high static and dynamic quality down to standstill have just started to be in use in industry. This paper presents a description of the properties of PSM drives using the INFORM® method for sensorless zero-speed control even for torque-, speed and even position-controlled applications. It is shown that the method is able to ensure highly transient operation even at high torque (up to a few times of rated torque) in the low-speed range. Evaluating the statistical properties of the method [Figs. 5, 7] yields probabilities of failures during the lifetime of the drive depending on the “INFORM quality” of the PSM as well as on the dynamic load properties of the application. An industrial example shows the advantageous application of the method in a positioncontrolled series application.

An Alternative to High Frequency Current Detection Techniques for Zero Speed Sensorless Control of AC Motor Drives  [Details]
By A. Consoli; A. Testa

The paper presents the main features of the Zero Sequence Technique (ZST), a sensorless algorithm for AC motor drives able to work at low and zero speed with full torque capability. The proposed method is different in principle than any other sensorless technique and much simpler on the implementation aspects, although it still belongs to the class of air gap flux estimators. A distinctive characteristic of the approach is that it also allows us to detect the amplitude of the air gap flux, thus exploiting full flux sensing capability not limited to only flux position estimation. Experimental and Finite Element Analysis results validate the performance of the method in comparison with standard sensorless techniques based on detecting the amplitude variation of high frequency currents.

Lamination Design Variations for Improved Performance of Zero Speed Sensorless Controlled Induction Machines  [Details]
By Th. M. Wolbank; R. Woehrnschimmel; J. L. Machl

To realise a high-dynamic controlled operation of induction machines the flux position has to be estimated during operation of the drive. Omitting the shaft sensor leads to a deterioration of the performance at low fundamental frequencies if fundamental wave models of the machine are applied. To determine the flux position at zero speed without shaft sensor it is thus necessary to use parasitic, non-fundamental wave effects of standard induction machines, such as spatial saturation, slotting, or other anisotropy. These effects are not evident in normal operation but can be exploited using the high frequency or transient electrical behaviour of the machine. All sensorless zero speed schemes currently published thus make use of a high frequency or transient excitation of the machine in addition to the fundamental wave, which are both impressed by the inverter. The machine reaction on this high frequency excitation is measured and the flux and/or rotor position signal estimated using special algorithms and signal processing techniques. However, it turned out in the past that the shape of the lamination and especially the slot geometry have strong influence on the high frequency/transient electrical response of the machine. Before realising a sensorless controlled drive it is thus advantageous to have a look at the design of the machine as not any design is suitable for a specific sensorless control algorithm. The presented investigation is thus focused on the influence of the lamination geometry on the resulting signals of a sensorless control scheme. The sensorless control method applied is usually denoted as INFORM-method in literature and is based on a transient excitation with voltage pulses. In the transient electrical current response of the machine there are always all saliencies present. The two most prominent saliencies are caused by saturation and slotting. Their modulations in the control signals have to be extracted and separated in order to obtain the flux or the rotor position of the machine. Currently the interaction of the saliencies limits the practical application of these methods. To investigate the mentioned influence, measurements have been performed on five machines with different lamination geometry. By comparing the extracted saliencies of these machines, the influence of slot design on the sensorless control signals is depicted. Thus the magnitudes of the two saliencies can be influenced by a proper adjustment of the geometry. This association is shown for the saturation saliency in Fig. 1. Depending if the flux or rotor position is to be used for the machine control the corresponding saliency can be boosted and the others attenuated. This results in a more reliable extraction and separation of the saliencies and a more robust control.


 EPE Journal Volume 13-3 - Products and Applications 

PSCAD and Transmission Lines  [Details]
By F. Foucher

PSCAD and Transmission Lines, by Fabrice Foucher, CEDRAT Support Team