ISSN 10683712, Russian Electrical Engineering, 2013, Vol. 84, No. 10, pp. 542–548. © Allerton Press, Inc., 2013.
Original Russian Text © Yu.I. Khokhlov, M.Yu. Fedorova, A.V. Khlopova, 2013, published in Elektrotekhnika, 2013, No. 10, pp. 12–18.
Powerful networkdriven polyphase converting
devices are widely used in powersupply systems of
electricalprocessing installations and transport
equipment. They are used in plants for aluminum,
nickel, magnesium, copper, etc., electrolysis in non
ferrous metallurgy; for electrolysis of chlorine, hydro
gen, caprolactam, etc., in the chemicals industry; in
electrothermal plants for electric graphitization of
electrodes; and in steelmaking, etc., as well as in the
gasandoil producing industry and in electric railroad
and public transport. Polyphase units are based on
12phase converters. In turn, the latter comprise, as a
rule, two sixphase converting units based on a bridge
or a neutral circuit.
In uncompensated converters, selfswitching of the
valves occurs that is affected only by the voltages of the
AC supply mains or receiving network. The converters
of this kind are the simplest. However, they have a
number of major drawbacks that necessitate improv
ing the converters’ basic characteristics in both recti
fier and inverter operating regimes. One effective way
to upgrade converters is introduction of forced single
stage commutation of the valves by voltages at the
compensating device’s capacitors added into the com
mutation circuit. Numerous works have resulted in a
developed theory of electromagnetic processes in con
verters with a forced singlestep commutation of the
valves (in compensated converters), for example, [1–3].
These developments, however, primarily concern con
verters in which the compensating devices (CDs) are
supplements to individual sixphase converting units.
We, guided by the experience that has been gained,
set ourselves the task of showing possibilities for
upgrading the characteristics of polyphase converters
by introducing compensating devices into the circuits
common for two sixphase converting units [4–10]
and by reactor control of the spectral distribution of
the currents and voltages at the capacitors of these
devices. Such an improvement of the characteristics of
polyphase converters for the above energyintensive
consumers is aimed at enhancement of energy effi
ciency and reliability of the powersupply systems.
A circuit schematic of a version of the diode sym
metrical compensated 12phase rectifiers (SCRs) is
shown in Fig. 1. The rectifier comprises two sixphase
converting units. The first unit is composed of a power
winding, the transformer’s deltaconnected valveside
windings, and rectifier bridge RB1. The second unit
consists of a power winding, the transformer’s star
connected valveside windings, and rectifier bridge
RB2. The compensating device common for both
units consists of a reactor with two operating windings
OW1 and OW2, one compensating winding CW, and
capacitor bank CB. The rectifier bridges relative to the
load are parallelconnected via a paralleling reactor
(PR), which is practicable for consumers with low
voltage and high load current levels. Otherwise, the
rectifier bridges are seriesconnected without a PR.
On Some Useful Qualities of 12Phase Converters
with a Controllable Ensemble of Harmonics
in a Compensating Device Common for SixPhase Units
Yu. I. Khokhlov
, M. Yu. Fedorova
, and A. V. Khlopova
South Ural State University, Chelyabinsk, 454080 Russia
Received September 16, 2013
—The circuitry of one of the 12phase converters with reactor control of an ensemble of current and
voltage harmonics in a compensating device common for two sixphase units is set out. Time diagrams and
basic characteristics of the converter are presented. The advisability of using converters with an ensemble of
odd harmonics is shown for the consumers of the direct current power located in a region adjacent to a power
supplier. For distant power consumers, use of converters with an ensemble of even harmonics is suggested.
For the purpose of improving the stability of the inverter regime when recovering electric power into the sup
ply mains, the practicability of using thyristor converters with an ensemble of even harmonics is demon
strated. Some examples of engineering and design solutions are presented by the example of a compensating
device reactor for a converter with an ensemble of odd harmonics.
: 12phase converter, sixphase unit, ensemble of odd harmonics, ensemble of even harmonics, rec
tifier, inverter, compensating device, powersupply system, reactor, engineering solution
The original version of this article was revised: A previously
missing affiliation was added.