In this study, there is a sensorless speed measurement in
DC motor is described. The proposed is based on the AC ripple
component of the motor current, which is used to detect the
ripple frequency because it is related to the speed of the motor.
The feasibility of the proposed speed measuring method is
evaluated in different applied voltage sources. The obtained
results with the same employed motor in different measuring
methods show that they are very similar. The manufacturing
cost and structure becomes higher, the allowable installed
space of speed sensor is limited and the measuring efficiency
may be then reduced. In fact, not all kind of sensors are always
allowed to be installed in the equipment. The speed
measurement of equipment like DC motor with a real speed
sensor is sometimes not suitable. Furthermore, the equipment
maybe hope to promote the operating performance and
required to be dynamically sampled the speed of equipment
where no free space exists. The proposed sensorless speed