This paper presents a historical and philosophical perspective on a possible future for power electronics. Technologies have specific life cycles that are driven by internal innovation, subsequently reaching maturity. Power electronics appears to be a much more complex case, functioning as an enabling technology spanning an enormous range of power levels, functions and applications. Power electronics is also divided into many constituent technologies. Till now, the development of power electronics has been driven chiefly by internal semiconductor technology and converter circuit technology, approaching maturity in its internally set metrics, such as efficiency. This paper examines critically the fundamental functions found in electronic energy processing, the constituent technologies comprising power electronics, and the power electronics technology space in light of the internal driving philosophy of power electronics and its historical development. It is finally concluded that, although approaching the limits of its internal metrics indicates internal maturity, the external constituent technologies of packaging, manufacturing, electromagnetic and physical impact, and converter control technology still present remarkable opportunities for development. As power electronics is an enabling technology, its development, together with internal developments, such as wide bandgap semiconductors, will be driven externally by applications in the future.

On a Future for Power Electronics

Self-excited induction generators (SEIGs) are increasingly being used in small-capacity isolated applications for harnessing both conventional and renewable energy resources. These SEIGs suffer from poor voltage regulation even when driven by constant speed prime movers or fixed head hydro turbines. The suitability of these SEIGs to regulate the terminal voltage is a key factor in deciding its use in various applications. This paper deals with the voltage-regulating (VR) schemes for SEIGs, which are found scattered in the literature, and summarizes their operational aspects and relative suitability. These VR schemes are classified on the basis of shunt and series compensation as classical schemes, schemes based on solid-state switching devices, and schemes based on self-commutating solid-state switching device converters. The recommendations drawn from this study are helpful in developing a new cost-effective regulating scheme of SEIGs for different industrial applications.

A Prospective on Voltage Regulation of Self-Excited Induction Generators for Industry Applications

Distinctive attributes of power electronics equipment are high power capability, controllability and static switching to meet the goals of high efficiency and high dependability. Aspects of the early history of power electronics are traced from magnetic amplifiers, thyratrons, and ignitrons to power semiconductors.

The evolution of power electronics

Electromechanical interaction in rotordynamics of cage induction motors

Variable frequency AC motor drives are recently making a tremendous impact in the industrial automation of nations. The rapid evolution of the technology could be possible because of many innovations in power semiconductor devices, power converter topologies, microprocessors, application specific IC's, control and computer-aided design techniques. The paper gives a brief but comprehensive state-of-the-art review of AC machines, power converter circuits and power semiconductor devices. The control and estimation issues with particular emphasis of induction motor drives are discussed. Finally, a few selected drive applications are reviewed. Variable frequency drives are expected to have increasing influence on a nation's industrial productivity, energy conservation, environmental protection and urban pollution problems in the coming decades. >

Variable frequency drives-technology and applications

Some of the early electronic power converters utilized mercury-arc rectifiers such as thyratrons and ignitrons. Their use in an-ac adjustable-speed drive began about 50 years ago. The first commercial application in the United States was made to an induced draft fan at the Logan station. This drive was in service for about 25 years. The early history of ac adjustable-speed drives which employed electronic power conversion is reviewed.

AC Adjustable-Speed Drives with Electronic Power Converters-the Early Days

http://ieeexplore.ieee.org/iel5/28/4504399/04504412.pdf

AC Adjustable-Speed Drives withElectronic Power ConvertersThe EarlyDays

The increasingly frequent use of larger four-pole and six-pole synchronous motors to drive high speed equipment, such as compressors, has focused much attention on coordination of the motor and driven equipment system. A relatively straight forward analytical method of calculating the motor-developed air-gap torque from the d and q axis equivalent circuits is presented. The problem of relating air-gap torque to shaft torque is discussed briefly, and methods of experimentally determining both quantities are presented. A method of assessing the capability of a shaft section to withstand a given torsional duty is also presented.

Torsional Coordination of High Speed Synchronous Motors-Part II

It is pointed out that most small electric machines are designed to rigid shaft criteria without any concern for possible effects on operating performance. However, an increasing number of large high-speed motors that operate at constant speed are designed to be flexible shaft machines. For those machines that operate at constant speed, flexible shaft design may be a good approach. However, flexible shaft motors may not be well suited to adjustable-speed operation because excessive vibration may occur at some operating speeds. The drive may have certain ranges of operation speed that cannot run continuously because of the high vibration. Rigid shaft motors have the advantage of being less prone to excessive vibration when operated over a wide speed range. With proper coordination and system design, rigid shaft motors operating on resilient mountings can be made insensitive to vibration. Hydrodynamic bearings can provide the required resilience if the rotor system is properly designed. Experience with such drives has not shown a need to forbid continuous operation for certain speed ranges. >

Edward L. Owen

Papers

AC Adjustable-Speed Drives with Electronic Power Converters-the Early Days

AC Adjustable-Speed Drives withElectronic Power ConvertersThe EarlyDays

Torsional Coordination of High Speed Synchronous Motors-Part II

Flexible shaft versus rigid shaft electric machines for petroleum and chemical plants

Induction Generator Applications forPetroleum and Chemical Plants