Konrad Urbanski

Adaptive observer of rotor speed and position for PMSM sensorless control system

This paper deals with the problem of rotor speed and position detection in sensorless permanent magnet synchronous motor (PMSM) drives. A concept based on detecting the back EMF induced in stator windings was developed and modified. A general structure of an adaptive observer with the proportional‐integral function of a corrector is introduced. The non‐stationary character of the observer presented in this paper requires an adaptive change of observer corrector settings. Such observer structure was implemented on a DSP system and verified experimentally. Both simulation and experimental results show good properties of the proposed observer structure.

Sensorless control of PMSM high dynamic drive at low speed range

The paper deals with the problem of rotor position and speed detection in sensorless PMSM drive at low speed range. Additional problem is to obtain high dynamic of proposed drive system. Achieving of the low calculation time of control algorithm is very important for high dynamic drives because of fast change of operating point, so observers equations should be quite simple. At this paper the “high dynamic drive” means such drive, which nominal torque to total moment of inertia ratio gives possibility to start up to nominal speed not exceed several dozen of milliseconds. A concept based on detecting the back EMF induced in stator windings was developed and modified. The observer structure contains a corrector with a proportional and multi integral function instead of the proportional one used with the extended state formula in the Luenberger observer. The research was realized using MATLAB ® Simulink environment.

Application of fuzzy control technique to thyristor DC drive

In the paper, a study of a fuzzy logic controller (FLC) application for the solution of some of the control problems of thyristor DC drives is presented. The control problems, which are taken into account during FLC synthesis, consist in the variable structure of the current control plant and variation of the moment of inertia in the speed control loop. Comparison between fuzzy control systems and traditional digital cascade control, carried out by a simulation method, proved that FLC as a robust control scheme gives better performance in the range where nonlinearity and parameter variation are observed.

Artificial neural network based robust speed control of permanent magnet synchronous motors

Purpose – The aim of the paper is to find a simple structure of speed controller robust against drive parameters variations. Application of artificial neural network (ANN) in the controller of PI type creates proper non‐linear characteristics, which ensures controller robustness.Design/methodology/approach – The robustness of the controller is based on its non‐linear characteristic introduced by ANN. The paper proposes a novel approach to neural controller synthesis to be performed in two stages. The first stage consists in training the ANN to form the proper shape of the control surface, which represents the non‐linear characteristic of the controller. At the second stage, the PI controller settings are adjusted by means of the random weight change (RWC) procedure, which optimises the control quality index formulated in the paper. The synthesis is performed using simulation techniques and subsequently the behaviour of a laboratory speed control system is validated in the experimental set‐up. The control ...

Sensorless control of PMSM fed through the sinusoidal filter

The paper presents results of a research on the sensorless drive with PMSM supplied through the sinusoidal filter. The back electromotive force based observer is used to the shaft position estimation. Used in the study, the observers correction function, contains multi integrators in the path, which improves the position estimation. Otherwise than in a typical implementation of the position observer, the presence of the filter was not taken into account in observer structure, however, it was taken into account in the observer parameters. This type of control allows the use of conventional control system and there is no need to take account the filter in the control circuit. Presented concept has been proven in laboratory.

Position estimation at zero speed for PMSM using probabilistic neural network

The paper presents a method for estimating the shaft position of a synchronous motor with permanent magnets (PMSM) for the zero and very low speed range. The method is based on the analysis of the high frequency currents, which are induced by the additional test voltage in a stationary coordinate system associated with the stator. Although this method involves the identification of currents hodograph, the method does not need to calculate the current ellipse position. Presented method involves a comparison of obtained shape to the reference pattern using probabilistic neural network (PNN). The method can achieve satisfactory accuracy in a case the high asymmetry of the inductance, as well as in the case of small values of the inductance asymmetry ratio, also in the case of a high level of noise.

Sensorless control of PMSM for low speed range

Purpose – The purpose of this paper is to develop the Permanent Magnet Synchronous Motors drive which has possibility to work in sensorless mode at low speed based on back EMFs estimation. Design/methodology/approach – Estimation uses modified Luenberger observer and the preprocessing of the EMFs before calculating the speed, using derivative and the Kalman filter (KF) to obtain smooth waveform of the estimated speed. This modification is needed because of the nonlinear change of the estimated back EMFs amplitude as a function of speed, in low-speed range. Findings – How to use back EMF observer to estimate a speed in the low-speed range was found in the course of the work. Simple and effective algorithm uses KF and can work even with a relatively big deformation of the estimated back EMF. Practical implications – Such sensorless drive may be used in low-cost constant or variable speed drive in domestic use or industrial application. Such drive may work properly where there is no initial load torque and t...

Speed and position estimation of SRM

The paper deals with the problem of speed and position estimation in SRM drive equipped with hysteresis band current controller. Instead of measured current the observer utilize reference current. The voltage is calculated from switching on-time. A speed observer structure which uses estimated back EMF and current of each phase is presented. The shaft position is integrated from estimated speed signal.

Fuzzy control of current in thyristor DC drive

In the paper an application of fuzzy logic controller (FLC) for control of thyristor DC drive is presented. During synthesis of the FLC a robustness against variation of structure of the current control plant was taken into account. Comparison between the fuzzy control system and an ordinary digital control system, carried out by simulation method, proved that FLC as a robust controller gives better performance in the range where non‐linearity and parameter variation is observed. The simulation results were confirmed by the laboratory experiment.

Improved Method for Position Estimation Using a Two-Dimensional Scheduling Array

The paper presents results of studies on the position estimation for the permanent magnet synchronous motor (PMSM) drive using gain scheduling technique for tuning the observers parameters. It allows a good estimation accuracy in wide range of working point change. Such observer with multi integral correction function improves the performance, but need to modify its parameters according to its speed and load. Novelty is the use of a two-dimensional gain scheduling technique and the use in the sensorless drive, where traditional solution is simple one-input scheduling variable—mainly on drives with position sensors. The look-up table output is processed using bilinear interpolation. Position observer is based on back EMF estimation. It uses predefined reference matrices of parameters, which are interpolated and depend on drives operating point.