A SLIDING MODE CONTROL OF BRUSHLESS DC MOTORS
APLIED IN DENTAL MICROMOTOR SYSTEMS
, Goce V. Shutinoski
OKTA – REFINERY Skopje,
SS. Cyril and Methodius University, Faculty of Electrical Engineering, Karpos II bb, P.O.B 574, 1000
– Analysis and simulation of sliding mode
controlled brushless DC motor (BLDC) applied in
dental equipment is presented. Comparison of the
main characteristics of the brushless (BLDC) versus
brush-type DC motor (BDC) under various
operating conditions shows certain advantages of
BLDC over BDC in dental specific micromotor
– Brush-type (BDC) Direct Current motor,
Brushless (BLDC) DC motor, Sliding Mode
One of the most utilized parts of the equipment in
dentist’s everyday practice is the micromotor. It is a
rotating energy source applied in the main dental
instruments used for drilling teeth, cutting bones or
similar dental tasks. These micromotors must satisfy
several working requirements among which the most
important are the equipment robustness and the speed
constancy independently of the presented load. They
must operate at safely low voltage, and must give the
possibility of setup the required speed by the dentist.
They need to be small, light and quiet as well and to
exhibit no vibrations in performing precise movements,
The micromotors mostly used in the past were those
with brush-type DC motors, since they have relatively
low market price and were suitable for mass
production. However, this type of motors exhibits
limitations both in the rotating speed and in the torque
as a consequence of the sparking brushes and because
the driving windings are located at the rotating part.
It is generally known that the brushed micromotors are
working at lower speed, accelerate slower, dissipate
higher heat power, they support lower torque and they
are much heavier in comparison to brushless types, .
From the dentist point of view this means undesirable
vibrations, inaccurate movements and lower efficiency
in their everyday work.
All of these characteristics make them worst choice for
dental application in comparison to BLDC motors.
That is why nowadays more and more the BLDC
based micromotors are replacing the BDC, , .
In the next section the general scheme of BLDC
based system is presented and described by its state
equations. Followed by the theoretical analysis of the
sliding mode control, one possible model used for
simulation is explained. Results obtained from
simulation of a model in “MATLAB” under various
appropriate conclusions about the application of BLDC
in dental “micromotor“ application are outlined.