POLITECHNIKA WARSZAWSKA

1. Introduction
dynamic performance of the speed control loop. The advantages of such sensorless
speed control drive can be summarized as follows:
- lower cost,
- reduced size of the drive motor,
- elimination of the sensor cable,
- higher reliability.
In recent years a lot of methods have been developed which allows to eliminate speed
sensors, because in many industrial applications it is neither possible nor desirable to
use a mechanical sensors. These methods can be generally divided in two groups:
closed loop sensorless speed control where the motor speed is estimated from other
measurable quantities as stator voltage and currents and open loop speed control with
slip compensation where the motor synchronous speed is controlled and the effect of
load torque changes on motor shaft speed is only compensated. For speed estimation
very often advanced observer technique or neural networks are applied. Slip
compensation methods, in contrast, are usually much simpler but cannot guarantee
good dynamic performances.
Among published papers only one is based on Neural Networks (NN) approach.
Therefore, the author has formulated the following tasks of the thesis:
• Basing on the Artificial Neural Network approach, development of the current
controllers in field oriented controlled PWM voltage source inverter fed
induction motor,
• Basing on the Artificial Neural Network theory, estimate the mechanical speed of
the induction motor, with the measuring of the stator currents and voltages.
In the both groups of problems the new original solutions have been proposed (the
author is the co-author of the patent no. P310512). To carry out this tasks at first the
simulation investigation have been performed, and after that the experimental set-up
has been design and the laboratory experiments have been done. Note that the
sensorless FOC of induction motor, described in this thesis, could be used in the high
performance motor drives of the electrical vehicles (for example hybrid cars) and in
the factories, in which the measurement of the mechanical speed is expensive or even
impossible.
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