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Über dieses Buch

This contributed volume is written by key specialists working in multidisciplinary fields in electrical engineering, linking control theory, power electronics, artificial neural networks, embedded controllers and signal processing. The authors of each chapter report the state of the art of the various topics addressed and present results of their own research, laboratory experiments and successful applications. The presented solutions concentrate on three main areas of interest:

· motion control in complex electromechanical systems, including sensorless control;

· fault diagnosis and fault tolerant control of electric drives;

· new control algorithms for power electronics converters.

The chapters and the complete book possess strong monograph attributes. Important practical and theoretical problems are deeply and accurately presented on the background of an exhaustive state-of the art review. Many results are completely new and were never published before. Well-known control methods like field oriented control (FOC) or direct torque control (DTC) are referred as a starting point for modifications or are used for comparison. Among numerous control theories used to solve particular problems are: nonlinear control, robust control, adaptive control, Lyapunov techniques, observer design, model predictive control, neural control, sliding mode control, signal filtration and processing, fault diagnosis, and fault tolerant control.



Electric Drives and Motion Control


Sensorless Control of Polyphase Induction Machines

The basics of transformations of polyphase systems into orthogonal systems are explained. Vector models of induction machines in orthogonal planes are analysed and multiscalar models for rotor flux and main flux together with stator current are presented. A speed observer based on an extended model of the induction machine for selected variables is applied in the control system for the induction machine. On the basis of the model developed for a three phase machine, a multiscalar model for a five phase machine is presented. The control system acts on the basis of the model for the first sequence of phases achieving speed control. The model for the second sequence of phases is used to synchronize the fluxes in orthogonal planes. Near trapezoidal flux distribution in the air gap is achieved independently of the machine load. All variables used in the control system are estimated using the speed observer for the first sequence and the Luenberger observer for the second sequence. The properties of the control systems are explained using examples of transients generated by simulations.
Zbigniew Krzeminski

Adaptive Position Tracking with Hard Constraints—Barrier Lyapunov Functions Approach

A servo control with unknown system parameters and constraints imposed on the maximal tracking error is considered. The barrier Lyapunov functions approach is applied to assure the preservation of constraints in any condition. The system’s performance is examined for three methods of controller design based on: quadratic Lyapunov functions; on barrier Lyapunov functions if only position constraints are imposed; and on barrier Lyapunov functions if both position and velocity constraints are present. The tuning rules are discussed and several experiments demonstrating features of the proposed control and the influence of the parameters are presented.
Jacek Kabziński, Przemysław Mosiołek, Marcin Jastrzębski

Predictive Position Control of a Two-Mass System with an Induction Motor in a Wide Range of Speed Changes

In the chapter issues related to the application of the Model Predictive Control (MPC) to position control of a drive system with an induction motor (IM) coupled to a load machine through a long shaft are presented. After a short introduction the mathematical model of IM is demonstrated. Then, the standard MPC algorithm is described in detail. Next, the proposed MPC-based position control structure is introduced. Contrary to the classical cascade structure with independent position and speed control loops, one MPC controller which regulates those two variables is designed. An additional fuzzy block allowing adaptation of MPC parameters is used. The tested MPC controller cooperates with DTC-SVM (direct torque control—space vector modulation) strategy of electromagnetic torque regulation including operation in the field weakening regions. The theoretical considerations are supported by a variety of simulation and experimental tests.
Piotr Serkies, Krzysztof Szabat

Selected Methods for a Robust Control of Direct Drive with a Multi-mass Mechanical Load

Mechanical vibrations represent one of the key issues in the development of direct drives with a complex mechanical structure, i.e., with non-stiff connections between motor and driven mechanisms and with variable moments of inertia. A solution for motion control in relation to a direct drive, with highly dynamic performance, coupled with multi-mass mechanical load is proposed in the chapter. Due to high resonance frequencies that are difficult to be actively damped by the control system, an original solution is proposed, which is based on damping the highest resonance frequencies with a specially selected and tuned filter, leaving the damping of the lowest frequencies to the control system. In the first part of this chapter, the identification method is presented, along with robust notch filters, which are tuned for the whole range of parameter variability. Due to variable moment of inertia, two robust control methods are proposed in the second and third parts of this chapter: one is based on an adaptive neural speed controller, while the other is based on a terminal sliding mode control (SMC). The online learning neural speed controller is based on the resilient back propagation (RPROP) algorithm. A modified terminal sliding control law is proposed for a system with delays and unmodelled dynamics. The advantages of both solutions are verified on the basis of experiment investigations.
Stefan Brock, Dominik Łuczak, Tomasz Pajchrowski, Krzysztof Zawirski

Electric Drives and Fault-Tolerant Control


Fault-Diagnosis and Fault-Tolerant-Control in Industrial Processes and Electrical Drives

This chapter presents a discussion of general methods applied in fault-diagnosis and fault-tolerant control systems. First the data-driven methods and model-based schemes are shortly addressed. Next the main fault-detection and fault-diagnosis methods for controlled plants are characterized. In the following part of the chapter fault-tolerant-control methods, using passive and active concepts, are described and evaluated. At the end, the above methods are discussed from the point of view of electric drives. The main faults occurring in AC motor drives are listed and characterized. Some issues related to fault-tolerant-control of electrical drives are illustrated and discussed.
Teresa Orłowska-Kowalska, Czesław T. Kowalski, Mateusz Dybkowski

IGBT Open-Circuit Fault Diagnostic Methods for SVM-VSI Vector-Controlled Induction Motor Drives

In this chapter a two-level three-phase voltage inverter fed induction motor drive is considered and a discussion of IGBT open-circuit faults diagnostic methods based on voltage and flux vector hodographs analysis is presented. These techniques have been validated for the drives with Direct Torque Control and Direct Rotor Field Oriented Control strategies. Additionally, a speed of the diagnosis has been considered and the post-fault strategy has been addressed.
Piotr Sobański, Teresa Orłowska-Kowalska

Speed and Current Sensor Fault-Tolerant-Control of the Induction Motor Drive

In this chapter a rotor speed and stator current sensors faults detection systems for a vector controlled induction motor drive are described and tested. Different active algorithms are discussed, their advantages and disadvantages are demonstrated from the drive safety point of view. Another problem, presented in this chapter, is focused on the fault detection time. Simulation results show that the proposed detection systems can be used in fault tolerant control algorithms. The simulation studies are confirmed through a variety of experimental tests.
Mateusz Dybkowski, Kamil Klimkowski, Teresa Orłowska-Kowalska

Stator Faults Monitoring and Detection in Vector Controlled Induction Motor Drives—Comparative Study

This chapter deals with the stator winding faults detection in the induction motor drives working in the closed speed control loops, with the direct field oriented control—DFOC or with the direct torque control—DTC. In order to detect the early stage of stator winding inter-turn short-circuits, the analysis of characteristic components of the stator currents spectra, as well as the control signals of the DFOC structure, are used for diagnostic purposes. Experimental results obtained from a specially prepared induction motor working under vector control are presented.
Marcin Wolkiewicz, Grzegorz Tarchała, Czesław T. Kowalski, Teresa Orłowska-Kowalska

Detection and Compensation of Transistor and Position Sensors Faults in PM BLDCM Drives

During normal operation of a permanent magnet brushless direct current motor (PM BLDCM) drive some faulty modes can occur as a result of the failures of the position sensors and transistors of a voltage inverter supplying the motor. In this chapter the impact of these faults on the PM BLDCM drive system has been presented. The waveforms and FFT spectra of the stator currents, hodographs of the stator current space vector in the stationary reference frame following transistor faults and waveforms of signals determining the actual position of the rotor have been analysed in the chapter. Simple diagnostic and localization methods to identify a faulty part of the drive system have been proposed. The post-fault control has been analysed as well, it enables the drive system to continue its operation despite the diagnosed faults, because additional hardware circuits are used. This chapter presents simulation results validated by experimental testes conducted in a laboratory set-up.
Marcin Skóra, Czesław T. Kowalski

Design and Control of Power Converters


Advanced Control Methods of DC/AC and AC/DC Power Converters—Look-Up Table and Predictive Algorithms

This chapter is devoted to a modern look-up table and predictive control methods of three phase power electronic converters. The authors consider voltage source converters in two and three level configurations as well as a two level current source rectifier. Some of the methods concern DC/AC inverter fed induction and PMSM motors. The other methods described in this chapter are dedicated to the control of the AC/DC rectifier working as an Active Front End of an AC/DC/AC converter. The authors focus on the methods with a non-linear look-up table and predictive control due to their excellent dynamic properties (limited only by the physical parameters of controlled systems such as the value of the DC voltage, grid inductance or AC motor leakage inductance). Moreover, non-linear methods, especially the predictive ones, provide very good quality of control in steady states, i.e. lack of active and reactive power steady-state error (AC/DC) or torque error (in the case of DC/AC converters). Look-up table methods have been taken into consideration as they also ensure the above advantages in a relatively short calculation time. The selected look-up table and predictive methods are proposed for both 2-level and 3-level converters. All the described control methods have been illustrated by simulation results and laboratory tests confirming their characteristics.
A. Godlewska, R. Grodzki, P. Falkowski, M. Korzeniewski, K. Kulikowski, A. Sikorski

Active Power Filter Based on a Dual Converter Topology

This chapter presents a concept for a shunt active power filter (APF) that is able to more accurately map its input current in a reference signal, when compared to a typical filter solution. This can be achieved by interconnecting two separate converters, such that one of the converters corrects a total output current towards a reference signal. The output power of the auxiliary converter is much lower than power of the main converter, while its frequency response is extended. Thanks to the continuous manner of the operation of the auxiliary converter, among other items, pulse modulation components in the filter input current and the total harmonic distortion (THD) is minimized. These benefits are paid for by a relatively small increase in the system’s complexity and cost. This converter concept has been named “dual converter topology” (DCT). In this chapter, APF basics are presented, along with the results of simulation experiments and potential practical arrangements of the active filter.
Michał Gwóźdź

AC/DC/AC Converter with Power Electronics Current Modulator Used in DC Circuit for Renewable Energy Systems

In this chapter, the elaborated structures of the main circuit and control system of a power electronics AC/DC/AC converter, working as a coupling between the energy grid and a water turbine with an electric machine, are described. In aiming to ensure the high efficiency of this system, input and output converters with sinusoidal current were implemented. The input AC/DC converter is based on a diode rectifier with a power electronics current modulator in the DC circuit, while the output circuit is based on a transistor inverter. This solution is dedicated to high power systems. The chapter also presents an MPPT algorithm, which is elaborated and used to control the DC/DC converter. The chosen simulation and experimental results of the research is analysed.
Michał Krystkowiak, Adam Gulczyński

Power Electronics Inverter with a Modified Sigma-Delta Modulator and an Output Stage Based on GaN E-HEMTs

The chapter presents a conception of a power electronics inverter based on a modified sigma-delta modulator (SDM) being used in the inverter’s control block. The proposed modulator includes a comparator with dynamic hysteresis instead of a latched comparator, which is typically used in single-bit SDMs. Thanks to this feature, the resolution of the SDM output bit stream is, theoretically, unlimited. As a result, the value of the THD of an inverter output voltage (current) is much lower than that of a typical SDM solution. This benefit is not offset by an increase in the system’s complexity. Moreover, the control system is simpler than in the case of a conventional inverter. Due to the very high frequency of an SDM output bit stream, in a power stage of the inverter, the gallium-nitride (GaN)-based E-HEMTs (Enhancement mode High Speed Mobility Transistors) are implemented. However, in the case of a lower value of an inverter output power, an Si-based device is still the proper choice. In the chapter, the inverter control circuit basics, the results of simulation experiments and a possible practical arrangement of this one as a voltage-controlled voltage source (VCVS) are presented.
Michał Gwóźdź, Dominik Matecki

FC + TCR-Type Symmetrical Follow-Up Compensator of the Fundamental Harmonic Reactive Power—Analysis and Experiment

The chapter presents results of analyses, simulations, and experiments concerning a FC + TCR-type symmetrical follow-up compensator of the fundamental harmonic reactive power in which a three-phase bridge rectifier with two additional thyristors (6T + 2T) was used as the adjustable inductive component. The research pertain to the three-phase 6T + 2T bridge rectifier circuit with the neutral wire led out, where selection and application of the appropriate developed thyristor controlling algorithm (introduction of an additional control angle δ) enables current flow outside supply source phases in those instants of time when output voltages of the star rectifiers have instantaneous negative values. The effect of minimization of rms and the reactive power component of the fundamental harmonic of source currents consists in a reduction of reactive load introduced by 6T + 2T bridge rectifier with respect to 6T bridge with the possibility to control it by choosing an appropriate value of angle δ. To obtain a lower content of harmonics in the power grid current, it has been proposed to couple a 5th and 3rd harmonics filter on the converter. Such a converter, equipped with filters with output terminated with a reactor and stabilizing the direct current value at different values of angle δ, can be used as a FC + TCR-type symmetrical follow-up compensator of reactive power. Regulation of reactive power in such a circuit is instantaneous. The paper ends with a presentation of applications developed in LabVIEW programming environment to visualize the principle of operation, take measurements, and results of laboratory research carried out with the compensator.
Malgorzata Latka

Switched Capacitor-Based Power Electronic Converter—Optimization of High Frequency Resonant Circuit Components

This chapter presents issues of optimization of the resonant circuit components’ volume in a switched-capacitor voltage multiplier (SCVM). The SCVM is derived from chip-scale technology but can effectively operate as a power electronic converter in a zero current switching mode when the recharging of switched capacitors occurs in a resonant circuit supported by an inductance. Selection of the passive LC components is not strictly determined, and depends on the optimization strategy according to the volume, efficiency or cost of the converter. Optimization of the volume of LC components is limited by the energy transfer ability via switched capacitors, thus by the rated power of the converter and switching frequency. Depending on the LC values, the converter operates in some specific states that determine the efficiency of the converter and voltage stress on semiconductor switches and diodes. This chapter presents analysis of the converter parameters and operation in the cases of optimization of the resonant circuit components’ values. The analytical discussion is also supported by the simulation and experimental results. All the results are provided for the SCVM but can be useful for a variety of switched-capacitor resonant power converters.
Zbigniew Waradzyn, Robert Stala, Andrzej Mondzik, Stanisław Piróg
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