Abstract:
There are different control systems for dealing with diverse disturbances and uncertainties
in engineering applications such as robotics and mechatronics, as well
as electronics. After Ohnishi discovered it in the middle of the 1980s, disturbance
observer (DOB) became one of the most prominent control approaches. PM synchronous
motor type is widespread in a variety of areas and offers several benefits,
such as a high power factor, high efficiency, robustness, and rugged construction.
Despite the fact that robust motor controllers are always implemented with microcontrollers
and computers, continuous-time analysis methods are widely used due to
their simplicity. The dynamics of disturbance estimation, or designing disturbance
obsever’s parameters, have a significant effect on the stability and performance of the
robust motor controller system. However, analysis in continuous time domain using
Bode Integral Theorem, which is usually employed for the understanding stability of
the control system, does not provide full information about stability. Focus of this research
is analysis the stability of a Speed based Disturbance Observer for Permanent
Magnet Synchronous Motors in the discrete-time domain by applying ten different
discretization approaches. The research will show the analysis and selection of appropriate
discrete time method for the motion control system with the application
to PMSM. Simulation and experimental results shows that some of the discretization
approaches provide better stability and performance than others. This thesis shows
that the choice of a discretization method can significantly impact the stability and
performance of a control system.