Heavy-duty trucks and self-propelled platforms are widely spread
for the purpose of transportation of heavy and bulky loads. Power
units of these vehicles consist of synchronous electric generators
(alternators) driven by diesel engines. The generator supplies
electricity to each motor-wheel of the vehicle and to all its
systems. Alternators are also used in cars' and trucks'
electric systems to supply their electric and electronic devices
(e.g., headlights, safety systems, etc.). Substantial reserves of
production and quality improvement of such alternators are hidden
in their tests technique improvement. In this paper, the software
is designed for mobile and stationary test stands of the
alternators. The software was created using "LabVIEW"
development system. It is designed to be used with "National
Instruments®" hardware. By manually or automatically, the
software allows receive: the no-load characteristic, the no-load
loss characteristic, the short-circuit characteristic, the
short-circuit loss characteristic, the V curves characteristic and
the load angle characteristic. It also allows to determine static
(right up to efficiency) and dynamic parameters during the tests.
The software consists of six virtual instruments (VIs) based on
specific algorithms which have been developed under the leadership
of the author of this paper. They include special adaptive
algorithm of sliding trigonometric interpolation which aim is to
filter noise of the input signals and draw curves for steady-state
and transient processes, and combined optimizing algorithm. That is
needed for reliable determination of the dynamic parameters based
on the results of the sudden short circuit test of the synchronous
generator. Nonlinear parameters (time constants) are determined by
using the alternating-variable descent method. Linear parameters
(initial values of transient processes) are determined analytically
at each step of nonlinear parameters optimization using earlier
derived formulas. The software is considerably extended for
stationary test stands, additionally based on "NI PXI"
programmable logic controller and static thyristor exciter with
micro-integrated system (e.g., "Simoreg DC Master"). In
the first place, it is due to the extra VI, which allows to cut
time of receiving machine's characteristic in automation mode.
The VI has a stator voltage control loop with PID controller which
provides significant forcing of the field with a desired value of
the overshoot. The algorithm optimization for PID control is also
included in the VI.
The software for receiving characteristics and determination of
static and dynamic synchronous machines' parameters was tested
by using simulated and also real information. The program tests
show that the error in determination of parameters will not exceed
5% for the noise level of 30% of the useful signal (stator winding
voltage).
Though the software was designed to be used with alternators, it
also can be used at test stands for synchronous motors and
condensers.