Jan Deskur

Damping of Torsional Vibrations in High-Dynamic Industrial Drives

Theoretical, design, and experimental aspects of the control of the drive with an elastic coupling are considered in this paper. Control structures suitable for application in industrial high-dynamic drives are developed. In such drives, the first resonance frequency can be higher than a hundred hertz, and the next frequency can be a thousand hertz or higher. The solution is oriented to industrial plants, whose computation ability is lower and signal delay is greater than in laboratory plants based on DSP. The authors discuss the problem and show methods of suppressing torsion vibrations in speed-control systems with only one sensor, i.e., a motor position encoder. The presented solution is based on an adequately designed PID controller.

Robust speed and position control of PMSM

In the paper, the problem of robust speed and position control of a permanent magnet synchronous motor is analysed. The idea of the proposed speed controller is based on the combination of sliding mode control with fuzzy logic rules. The introduction of an integral module to the sliding mode controller leads to fast system dynamics of slight sensitivity to the load parameters variation, effective chattering reduction and elimination of steady state control error. Fuzzy adaptive mechanism tuning a switching gain of sliding-mode controller reduces the speed dynamic error caused by change of load torque. Experimental results obtained during investigation of constructed laboratory stand verify theoretical results and prove good quality of speed and position control.

Application of digital phase locked loop for control of SRM drive

High performance SRM drive requires precise information concerning instantaneous rotor position. Sensors mounted internally by manufacturers of SRM, are often inaccurate and of low resolution. The substantial improvement of both: resolution and accuracy has been achieved by application of unconventional all digital phase locked loop (ADPLL), which has been implemented in complex programmable logic device (CPLD). The ADPLL is fully synchronized with supervising DSP-based control system for high-performance SRM drive. Such solution is very flexible; the PLL can be easily tuned with DSP or re-programmed in purpose to perform various control strategies. Some proposals for sensorless control with ADPLL are also presented in the paper. Usually, equations describing position estimator or observer are calculated in software. Our approach enables time-critical equations resolved in hardware and there are no limits for high-speed operation.

Speed controller for a drive with complex mechanical structure and variable parameters

The paper presents the problem of obtaining a good dynamics of the PMSM drive with complex mechanical structure and variable moment of inertia. Proposed approach bases on proper design of feedback filter to reduce influence of mechanical resonances and applying a neural speed controller trained online, which can adapt itself to variable inertia. As an alternative, robust PI controller with set-point weighting is presented. The results of simulation and experimental investigations show good properties of designed control system.

Modified sliding-mode speed controller for servo drives

In the paper a problem of robustness of sliding-mode speed control for AC drives is analysed. Some high sensitivity of sliding mode speed controllers to high frequency periodic disturbances is shown. The proposed modified structure of sliding mode controller bases on introduction of filtering module, what leads to good system dynamics of slight sensitivity to the load parameters variation, effective chattering reduction and elimination of steady state control. Proposed general structure is universal and can be applied not only in speed control systems. Results of computer simulation study proved low sensitivity of classical sliding mode controller to high frequency disturbances and showed clearly the advantages of elaborated control method. Experimental investigation of constructed laboratory stand verify theoretical investigations and prove main simulation results.

The problem of measurement and control of speed in a drive with an inaccurate measuring position transducer

The theoretical limitations of the speed control for drives equipped with an inaccurate, low-resolution position sensor (encoder) are analysed in this paper. Encoder errors as well as time delay introduced by the speed calculation method are considered. The conclusions arising from the theoretical analysis have been confirmed by simulation results.

Models of magnetic circuits and their equivalent electrical diagrams

The paper presents a method of creating electrical equivalent diagrams of magnetic circuits. The method is based on bond‐graph techniques, using flux derivative as flow variable. Couplings between magnetic and electric part of the system are represented by gyrators. Simple models of magnetic branches, including non‐linear effects due to saturation, hysteresis and eddy currents, are presented. These models can be easily combined into magnetic circuit models, which can be transformed into dual electric equivalent circuit. Various equivalent circuits of transformers are discussed. The proposed models are simple and particularly useful for system‐level simulation of power electronic and motion control systems with magnetic elements. These models can be easily developed if needed. Theoretical considerations are illustrated by examples of digital simulation and experimental results.

Optimal control of current switching angles for high‐speed SRM drive

Purpose – The purpose of this paper is to propose a method of optimal control of current commutation of switched reluctance motor drive.Design/methodology/approach – The problem of optimal current commutation control is solved by off‐line selection of switching‐on and switching‐off angles. Selection of optimal values of angles is provided on computer model of the drive with help of particle swarm optimisation method. The optimal angle values are detected as functions of phase current and rotor speed. These calculated optimal values are stored in microcomputer control system memory in form of two‐input look‐up tables. The results are validated on laboratory set up.Findings – Three different criteria of optimal control, which are taken into account: the maximum electromagnetic torque for given reference current, the maximum ratio of electromagnetic torque to root mean square value of phase current and the minimum electromagnetic torque ripples, gave a good results validated by simulation and experimental in...

Optimal control of current commutation of high speed SRM drive

The problem of optimal current commutation control, which bases on optimal off-line selection of switching angles, was investigated in the paper. Two different criteria of optimal control were taken into account: the maximum electromagnetic torque for given current and the minimum electromagnetic torque ripples. Optimization process was provided on base of computer model of SRM drive. Obtained simulation results were validated by experimental investigations.

The problems of high dynamic drive control under circumstances of elastic transmission

In the paper the theoretical, design as well as experimental aspects of the control of high dynamic drive with elastic coupling are considered. It is shown that the solutions of problem of vibration damping, suitable for the drives with low natural torsional frequency, give not good result at high dynamic. In this case the low frequency can be higher than several tens or 100 Hz and the next frequency of the multi-mass model can be thousand Hz and higher. Authors show the way of suppression of oscillations, based on the adequate PID speed controller. In the solutions only one sensor i.e. position encoder is used. The paper presents experience acquired during studying the problem, designing and investigating the laboratory plant based on the PMSM.