Bimal K. Bose

An adaptive hysteresis-band current control technique of a voltage-fed PWM inverter for machine drive system

An adaptive hysteresis-band control method where the band is modulated with the system parameters to maintain the modulation frequency to be nearly constant is described. Although the technique is applicable to general AC motor drives and other types of load, an interior permanent magnet (IPM) synchronous machine load is considered. Systematic analytical expressions of the hysteresis band are derived as functions of system parameters. An IPM machine drive system with a voltage-fed current-controlled PWM (pulse width modulation) inverter has been computer simulated to study the performance of the proposed method. >

Investigation of fault modes of voltage-fed inverter system for induction motor drive

The authors describe a systematic investigation into the various fault modes of a voltage-fed pulse-width-modulated (PWM) inverter system for induction motor drives. All the fault modes were identified, and a preliminary mathematical analysis was made for the key fault types-namely, input supply single line to ground fault, rectifier diode short circuit, inverter transistor base drive open, and inverter transistor short circuit conditions. The predicted fault performances were substantiated by a simulation study. The study was used to determine stresses in power circuit components and to evaluate satisfactory postfault steady-state operating regions. The results are equally useful for better protection system design and easy fault diagnosis.<<ETX>>

Expert system, fuzzy logic, and neural network applications in power electronics and motion control

Artificial intelligence (AI) tools, such as expert systems, fuzzy logic, and neural networks are expected to usher a new era in power electronics and motion control in the coming decades. Although these technologies have advanced significantly and have found wide applications, they have hardly touched the power electronics and machine drives area. The paper describes these AI tools and their application in the area of power electronics and motion control. The body of the paper is subdivided into three sections which describe, respectively, the principles and applications of expert systems, fuzzy logic, and neural networks. The theoretical portion of each topic is of direct relevance to the application of power electronics. The example applications in the paper are taken from the published literature. >

Neural Network Applications in Power Electronics and Motor Drives—An Introduction and Perspective

Artificial intelligence (AI) techniques, particularly the neural networks, are recently having significant impact on power electronics and motor drives. Neural networks have created a new and advancing frontier in power electronics, which is already a complex and multidisciplinary technology that is going through dynamic evolution in the recent years. This paper gives a comprehensive introduction and perspective of neural network applications in the intelligent control and estimation for power electronics and motor drives area. The principal topologies of neural networks that are currently most relevant for applications in power electronics have been reviewed including the detailed description of their properties. Both feedforward and feedback or recurrent architectures have been covered in the description. The application examples that are discussed in this paper include nonlinear function generation, delayless filtering and waveform processing, feedback signal processing of vector drive, space vector PWM of two-level and multilevel inverters, adaptive flux vector estimation, and some of their combination for vector-controlled ac drive. Additional selected applications in the literature are included in the references. From the current trend of the technology, it appears that neural networks will find widespread applications in power electronics and motor drives in future

Microcomputer Control of a Residential Photovoltaic Power Conditioning System

Microcomputer-based control of a residential photovoltaic power conditioning system is described. The microcomputer is responsible for array current feedback control, maximum power tracking control, array safe zone steering control, phase-locked reference wave synthesis, sequencing control, and some diagnostics. The control functions are implemented using Intel 8751 single-chip microcomputer-based hardware and software. The controller has been tested in the laboratory with the prototype power conditioner and shows excellent performance.

A high-performance inverter-fed drive system of an interior permanent magnet synchronous machine

A high-performance, fully operational four-quadrant control scheme for the interior permanent magnet (PM) synchronous machine is described. The machine operates smoothly with full performance in the constant-torque region as well as in the flux-weakening constant-power region in both directions of motion. The transition between the constant-torque region and the constant-power region is very smooth at all conditions of operation. Control in the constant-torque region is based on the vector stator flux, while constant-power region control is implemented through the feedforward vector rotator. The control system is digitally implemented using a distributed microcomputer system, and all of the essential feedback signals such as torque, flux, etc. are estimated with precision. A 70 hp drive system using a neodymium-iron-boron (NeFeB) PM machine and transistor pulse width modulation inverter was designed and extensively tested in the laboratory on a dynamometer, and performance was found to be excellent. >

Power Electronics and Motor Drives Recent Progress and Perspective

Power electronics technology has gone through dynamic evolution in the last four decades. Recently, its applications are fast expanding in industrial, commercial, residential, transportation, utility, aerospace, and military environments primarily due to reduction of cost, size, and improvement of performance. In the global industrial automation, energy conservation, and environmental pollution control trends of the 21st century, the widespread impact of power electronics is inevitable. It appears that the role of power electronics on our society in the future will tend to be as important and versatile as that of information technology today. In this paper, the importance of power electronics will be discussed after a brief historial introduction in the beginning. Then, the recent advances of power semiconductor devices, converters, variable-frequency AC drives, and advanced control and estimation techniques will be reviewed briefly. Unlike a traditional technology survey paper, the number of figures is kept intentionally small in favor of the text within the length constraint of this paper. The prognosis of different areas will be highlighted wherever possible based on the authors own knowledge and experience. In conclusion and future scenario, the trend of power electronics and motor drives along with some possible research and development areas will be highlighted.

Fuzzy logic based on-line efficiency optimization control of an indirect vector-controlled induction motor drive

Improvement of adjustable speed drive system efficiency is important not only from the viewpoints of energy saving and cooling system operation, but also from the broad perspective of environmental pollution. The paper describes a fuzzy logic based on-line efficiency optimization control of a drive that uses an indirect vector controlled induction motor speed control system in the inner loop. At steady-state light-load condition, a fuzzy controller adaptively decrements the excitation current on the basis of measured input power such that, for a given load torque and speed, the drive settles down to the minimum input power, i.e., operates at maximum efficiency. The low-frequency pulsating torque due to decrementation of rotor flux is compensated in a feedforward manner. If the load torque or speed command changes, the efficiency search algorithm is abandoned and the rated flux is established to get the best transient response. The drive system with the proposed efficiency optimization controller has been simulated with lossy models of the converter and machine, and its performance has been thoroughly investigated. An experimental drive system with the proposed controller implemented on a TMS320C25 digital signal processor, has been tested in the laboratory to validate the theoretical development. >

A fuzzy set theory based control of a phase-controlled converter DC machine drive

A description is presented of the application of fuzzy logic in a speed control system that uses a phase-controlled bridge converter and a separately excited DC machine. The fuzzy control is used to linearize the transfer characteristics of the converter in the discontinuous conduction mode occurring at light load and/or high speed. The fuzzy control is then extended to the current and speed control loops replacing the conventional proportional-integral (PI) control method. The compensation and control algorithms have been developed in detail and verified by digital simulation of a drive system. The simulation study indicates the superiority of fuzzy control over the conventional control methods. Fuzzy logic seems to have a lot of promise in the application of power electronics.<<ETX>>

Microcomputer Control of Switched Reluctance Motor

A microcomputer-based four-quadrant control system of a switched reluctance motor is described. The control was implemented with a speed feedback loop, a torque feedback loop, and both the torque and speed feedback loops combined. In addition the controller incorporates a startup operation, sequencing, and synchronized angle steering control. The angle controller was designed using dedicated digital hardware, whereas the other functions were implemented using an Intel 8751 single-chip microcomputer. The complete control system was tested in the laboratory with a 5-hp drive, and the test results were found to be excellent.