On state estimation in electric drives
Sliding mode control design principles and applications to electric drives .The basic concepts, mathematics, and design aspects of variable-structure systems as well as those with sliding modes as a principle operation mode are treated. The main arguments in favor of sliding-mode control are order reduction, decoupling design procedure, disturbance rejection, insensitivity to parameter variations, and simple implementation by means of power converters. The control algorithms and data processing used in variable structure systems are analyzed. The potential of sliding mode control methodology is demonstrated for versatility of electric drives and functional goals of control.
High-power and/or high-voltage electric drives. Multilevel converters: (1) can generate near-sinusoidal voltages with only fundamental frequency switching; (2) have almost no electromagnetic interference or common-mode voltage; and (3) are suitable for large voltampere-rated electric drives and high voltages. The cascade inverter is a natural fit for large automotive all-electric drives because it uses several levels of DC voltage sources, which would be available from batteries or fuel cells. The back-to-back diode-clamped converter is ideal where a source of AC voltage is available, such as in a hybrid electric vehicle. Simulation and experimental results show the superiority of these two converters over two-level pulsewidth-modulation-based drives.Multilevel converters for large electric drives .
Since 1994, the University of Minnesota has been undertaking a long overdue restructuring of power electronics and electric machines/drives courses. This restructuring allows digital control to be integrated into first courses, thereby teaching students what they need to learn, making these courses appealing, and providing a seamless continuity to advanced courses. By a concise presentation in just two undergraduate courses, this restructuring motivates students to take related courses in programmable logic controllers, microcontrollers and digital signal processor applications. On state estimation in electric drives .This ensures a first-rate education that is meaningful in the workplace as well as in graduate education leading to a research and development oriented career. This restructuring has several components to it. Outdated topics that waste time and mislead students are deleted. To integrate control in the first courses, unique approaches are developed to convey information more effectively. In the first course in power electronics, a building block is identified in commonly used power converter topologies.Restructuring of first courses in power electronics and electric drives that integrates digital control .
With nearly two-thirds of global electricity consumed by electric drives, it should come as no surprise that their proper control represents appreciable energy savings. The efficient use of electric drives also has far-reaching applications in such areas as factory automation (robotics), clean transportation (hybrid-electric vehicles), and renewable (wind and solar) energy resource management. Advanced Electric Drives utilizes a physics-based approach to explain the fundamental concepts of modern electric drive control and its operation under dynamic conditions. Author Ned Mohan, a decades-long leader in Electrical Energy Systems (EES) education and research, reveals how the investment of proper controls, advanced MATLAB and Simulink simulations, and careful forethought in the design of energy systems translates to significant savings in energy and dollars. Offering students a fresh alternative to standard mathematical treatments of dq-axis transformation of a-b-c phase quantities, advanced Electric Drives: Analysis, Control, and Modeling Using MATLAB/Simulink.
On one hand a nonlinear observer is designed, whereas on the other hand the speed state is estimated by using the dirty derivative from the position measured. The dirty derivative is an approximate version of the perfect derivative which introduces an estimation error few times analyzed in drive applications. For this reason, our proposal in this work consists in illustrating several aspects on the performance of the dirty derivator in presence of both model uncertainties and noisy measurements. To this end, a case study is introduced. The case study considers rotor speed estimation in a permanent magnet stepper motor, by assuming that rotor position and electrical variables are measured. In addition, this paper presents comments about the connection between dirty derivators and observers, and advantages and disadvantages of both techniques are also remarked.
Statistical method for electric machine optimization used for electric drives .
A method is provided for selecting and optimizing an electric drive system by analyzing critical-to-quality subjects of the electric drive system according to Six Sigma theory. The critical-to-quality subjects include weight, volume, reliability, efficiency and cost. Various design approaches may be evaluated to select an optimal design. The design approaches may include electric machine type, cooling system, electrical integration and electrical-mechanical interface.
Fundamentals of Electric Drives,presents the basic topics and fundamental concepts underlying electric machines, power electronics, and electric drives for electrical engineering students at the undergraduate level. On state estimation in electric drives .Most existing books on electric drives concentrate either on converters and waveform analysis (ignoring mechanical load dynamics), or on motor characteristics (giving short shrift to analysis of converters and controllers). This book provides a complete overview of the subject, at the right level for EE students. The book takes readers through the analysis and design of a complete electric drives system, including coverage of mechanical loads, motors, converters, sensing, and controllers. In addition to serving as a text, this book serves as a useful and practical reference for professional electric drives engineers.
Hardware-in-the-loop simulation is today a standard method for testing electronic equipment in the automotive industry. Since electric drives and power electronic devices are more and more important in automotive applications, these kinds of systems have to be integrated into the hardware-in-the-loop simulation. Power converters and electric drives are used in many different applications in vehicles today (hybrid electric or electric powertrain, electric steering systems, DC-DC converters, etc.). The wide range of applications, topologies, and power levels results in various different approaches and solutions for hardware-in-the-loop testing. This paper gives an overview of hardware-in-the-loop simulation of power electronics and electric drives in the automotive industry. The currently available technologies are described and future challenges are outlined.
Accurate measurement of power losses in high-efficiency devices is difficult. Measurement standards for industrial converters and complete electric drives, including both motors and converters, will come into effect soon, and measurement methods for these devices should be included. In the calorimetric method, the power losses are measured directly. However, the calorimeters presented previously are mainly tailored systems, and therefore, they typically have very complicated constructions. Hence, their applicability to the evaluation of general electric drives is limited.On state estimation in electric drives . A functional calorimetric measurement concept is suggested in this study for power losses up to 2 kW. Such a power loss can be applied with present-day power electronic converters up to 110 kW. The construction of the concept is simple and lightweight. It does not require a complex structure or a large area in the measurement site. The concept is scalable and duplicable for different sizes. Different devices with different cablings can be measured without any problems.Calorimetric concept for measurement of power losses up to 2 kW in electric drives .
Aux Boiler SIM 321 Digital Input 6ES7 321 -1BL00 - 2AA0 1
Aux Boiler SIM 321 Digital Input 32 CH 6ES7 321 -1BL00 - 0AA0 1
Aux Boiler SIM 321 Digital Input 16 CH 6ES7 321 -1BH02 - 0AA0 1
Aux Boiler SIM 322 Digital Output 32 CH 6ES7 322 -1BL00 - 0AA0 1
Aux Boiler SIM 322 Digital Output 16 CH 6ES7 322 -1BH01 - 0AA0 1
Aux Boiler SIM 331 Analog Input 8-Channel 24V 13Bit 6ES7 331 - 1KF01- 0AB0 1
Aux Boiler SIM 331 Analog Input 8 CH 6ES7 331 - 7KF02 - 0AB0 1
Aux Boiler SIM 331 Analog Input 8 CH 6ES7 331 - 7HF01 - 0AB0 2
Aux Boiler SIM 332 Analog Output 8 CH 6ES7 332 - 5HF00 - 0AB0 1
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Modern agricultural machinery has to perform in the most efficient way. Often they are already equipped with electronic control systems. The drives of today's agricultural implements are mainly mechanic or hydraulic. Recent developments and improvements in electric drives strengthen their applicability in agricultural machinery. Reduced fuel consumption as a result of high efficiency and the automated working procedures are of certain interest. In terms of system architecture so called agro-hybrid-structures can be derived from automotive-hybrid-systems. They have to be defined and selected in conjunction with the required functionality. Some basic results of a survey among Austrian implement and machinery manufacturers concerning the interest in electric drives and the potential will be presented.
Electric drive system with several units of driver is a main form of transmission control. Electric synchronous driving is often the key problem for the system. The basic principle of synchronous control and three kinds of synchronous control methods are presented in this article, and their characteristics are discussed in details.
The models are presented in equivalent circuit form to preserve the identity of nonlinear parameters. The circuits, designated as Γ or inverse Γ form, are simpler than the conventional T-form circuit. Their parameters are readily determined from terminal measurements. The major effects of magnetic nonlinearity are included in the models in a way that is more accurate than that usually obtained with the conventional T-form circuits. Modeling of time harmonics is also discussed.
Different types of Hardware-In-the-Loop simulation for electric drives 。Hardware-in-the-loop (HIL) simulations are more and more used to assess performances of electric drives. Software simulations lead to develop control of the studied system. In this case generally a lot of simplifications are assumed to reduce the computation time. Before a real-time implementation of the control, HIL simulations could be a very useful intermediary step. Thus a hardware device is introduced in the loop in order to take its real constraints into account. In this paper, three different kinds of HIL simulation are suggested: signal level, power level, and mechanical level. A example is given for the traction system of an electric scooter.
Signal identification is a common problem in electric drive applications. This paper proposes the use of wavelet transforms to extract and identify specific frequency components. Initially, current measurements from a constant voltage/hertz application are filtered using various wavelets and the results compared with conventional filtering methods. A pseudoadaptive denoising method is then proposed based on wavelets which adjust the level of decomposition depending on the rotor speed. Finally, wavelets are used in a high frequency injection speed estimation scheme and shown to be superior to conventional methods in such cases, where the useful information may be at higher frequency and have imprecise frequency components. Experimental and simulated results verify these statements.
Two issues are still a great challenge in the design and application of advanced controlled electric drives, namely, recovery of the braking energy and ride-through capability of the drive system. Apart from the ordinary solutions, such as back-to-back and matrix converters, an approach based on the ordinary diode front-end-drive converter equipped with an energy-storage element is used in some applications, such as traction and lift drives. This approach has come into focus recently with the rapid development of electrochemical double layer capacitors, so-called ultracapacitors. To achieve system flexibility and better efficiency, the ultracapacitor is connected to the drive via a dc-dc converter. The converter is controlled in such a way as to fulfill the control objectives: the control of the dc-bus voltage, the ultracapacitor state of charge, and peak-power filtering. In this paper, we have discussed the modeling and control aspects of the regenerative controlled electric drive using the ultracapacitor as energy-storage and emergency power-supply device.
Design of the speed controller for sensorless electric drives based on AI techniques: a comparative study The speed controllers based on (1) feed-forward neural network, (2) neuro-fuzzy network, and (3) self-organising Takagi–Sugeno (TS) rule based model are designed. A comparative analysis of the drive behaviour with these three types of AI based speed controllers is performed. In addition, a comparison is made with respect to the drive performance obtained with a conventional optimised PI controller. A detailed simulation study of a number of transients indicates that the best performance, in terms of accuracy and computational complexity, is offered by the self-organising Takagi–Sugeno controller. The controllers are developed and tested for a plant comprising a variable-speed separately excited DC motor.
From the EMC point of view, the integration of electric drive systems into today's cars represents a substantial challenge. The electric drive system is a new component consisting of a high-voltage power source, a frequency converter, an electric motor and shielded or unshielded high-power cables. Treating this new electric drive system or its components as a conventional automotive component in terms of EMI test procedures and emission limits would lead to substantial incompatibility problems. In this paper, the EMC issues related to the integration of an electric drive system into a conventional passenger car are investigated. The components of the drive system have been analyzed being either noise sources or part of the coupling path within the new electrical system of the car. The obtained results can also be used to determine the acceptable noise levels on a high voltage bus of an electric drive system.
Reduced harmonics PWM controlled line-side converter for electric drives A reduced-harmonics pulse-width modulator and its application to the control of a three-level line-side power converter for a speed-variable AC drive are described. The pulse-width modulation scheme for the voltage source inverter determines each individual switching instant on the basis of a continuously updated volt-second balance between the reference vector and the actual switching state vector. The generated pulse sequence is shown to be asynchronous. The Fourier spectra are characterized by the absence of high-amplitude discrete carrier components. The emission of acoustic noise radiated from magnetic components is reduced. Experimental results have been obtained from a transistor converter operated from the 660 V industrial power supply. The DC-link voltage is 1200 V.
Traditional two-level high-frequency pulse width modulation (PWM) inverters for motor drives have several problems associated with their high frequency switching which produces common-mode voltage and high voltage change (dV/dt) rates to the motor windings. Multilevel inverters solve these problems because their devices can switch at a much lower frequency. On state estimation in electric drives .Two different multilevel topologies are identified for use as a power converter for electric drives: a cascade inverter with separate DC sources; and a back-to-back diode clamped converter. The cascade inverter is a natural fit for large automotive all-electric drives because of the high VA ratings possible and because it uses several levels of DC voltage sources which would be available from batteries or fuel cells. The back-to-back diode clamped converter is ideal where a source of AC voltage is available such as a hybrid electric vehicle. Simulation and experimental results show the superiority of these two power converters over PWM-based drives.
The concept for a reduced-harmonics PWM modulator, as applied for the control of a line-side power converter for a variable speed electric drives, is described. The PWM algorithm determines the on-state duration of each switching vector based on the observation of the time-variable voltage reference vector. Since there is no reference made to a constant-frequency carrier signal, the generated pulse patterns become asynchronous. It is the essential property of this method to produce a quasicontinuous harmonic spectrum in which all frequency components have more or less equal magnitudes. This is an advantage as compared with carrier-based PWM control schemes that exhibit high-amplitude carrier and side-band components in their harmonic spectra. The emission of acoustic noise radiated from the AC filter inductor is reduced.
