Published in:
Electric Power Applications, IEE Proceedings B (Volume:133 , Issue: 6 )
Power electronics, control of the
electromechanical energy conversion
process and some applications
Prof. J.D. Van Wyk, Dr.sc.tech., Prof. H.-Ch. Skudelny, Dr.Ing., and
A. Muller-Hellmann, Dr.Ing.
Date of Publication:
November 1986
Professor: Ming-Shyan Wang
Student: Hao-Chun Chu
Outline
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Electronic processing of power
Power electronics: a proposed systematic approach
Development of the subject of machine electronics
Development of ideas to control electrical machines
Growth of power electronics in rail drives as an example
of application in the control of electric machines
State of the art and future trends in power and machine
electronics
Electronic processing of power
Power electronics covers a much wider field encompassing the
application of switching power to all types of loads. Electric
machines form but a small fraction of the loads found for power
electronic convertors.
Power electronics: a proposed systematic
approach
It has already been noted that efficiency and loss requirements
dictate the control of power in a switching mode in power electronics.
For a systematic approach the technology of the specific types of
power switches, as well as particular peculiarities of behaviour
should be omitted. These characteristics — such as switching speed,
switching
This leads to the fundamental possibility to control power flow as
shown in Fig. By operation of the switches Si and S2, the switching
function s(t) is generated, so that the load voltage becomes
uL{t) = s(t)us(t)
Development of the subject of machine
electronics
The oldest known switch used in the control of electrical machines is
the mechanical commutator. This was followed by a mechanical
switching arrangement to control the field of generators, the Tirrill
controller. Subsequently the gaseous valves showed promise for
generating the switching functions necessary to control machines.
These devices had some disadvantages and at a time it appeared
that the mechanical metallic rectifier (a modified commutator!) was
the future promise. Almost simultaneously it was succeeded by a
device developing in parallel, the transductor or magnetic amplifier.
The era of semiconductor switches then dawned, an era from which
we, being still concerned in its development, are able to derive but
limited historical perspective.
Development of ideas to control
electrical machines
Ideas to use electronic elements to control, regulate or augment
electrical machines appear to have been put into practice for the first
time around 1920. It is possible that these contributions may not be
characterised as machine electronics as it is known today, yet may
be considered as the very beginning of the subject.
One of the ideas being applied at present is the use of thyristor
frequency changers in conjunction with squirrelcage induction
machines for electric traction purposes.
Growth of power electronics in rail
drives as an example of application in
the control of electric machines
This last locomotive, representing a very important state
in the development, was equipped by the AEG Company.
The convertor was built in a particularly interesting circuit
arrangement. Four groups of four anodes worked on
different taps of the main transformer. Additionally a zero
anode was also available. The 18 anodes of a mercuryarc rectifier in a steel tank were connected as shown in
the Figure.
State of the art and future trends in
power and machine electronics
Although the art and science of electrical machines have for some
time been considered well known, the future possibilities for power
conditioning and conditioning and control of the electromechanical
energy conversion process is being affected profoundly by the
present and future developments in semiconductor technology,
especially with regard to power semiconductor devices and control
electronics, which have been aided by the developments in the field
of microelectronics. The discussion in the following sections will
centre on the different switching devices, the present and future
power convertor topologies, the present and future situation
regarding the use of convertors as machine actuators in control
systems, the present and future situation regarding control of DC
and AC machine drives, including adaptive control ideas, and, finally,
the interface between power and machine electronics and power
system technology.
Conclusion
New directions of development regarding the electronic conditioning
of the electromechanical energy conversion process concerning the
elimination of undesirable effects and losses are important. The
implementation of these trends by utilising the improved switching
characteristics of power electronic switches and the information
processing capability of microprocessors is discussed. This is then
extended toward control aspects, where both these characteristics
enable solutions not possible hitherto. Field control of AC machines
imparts control characteristics equal to, or better than, those
obtainable with DC machines to the systems, while the processing
capability of microprocessors allows the configuration of adaptive
machine electronic systems. Finally attention is given to the
interfacing of power electronic and machine electronic systems to
the power supply network. If the exponential growth of the installed
capacity of equipment in the future is to be handled, active
compensation of the distorted currents drawn from the supply by this
equipment will have to be considered seriously.
Source
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http://ieeexplore.ieee.org/xpl/articleDetails.jsp
?arnumber=4644248
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