ABSTRACT
The significant feature of the separately excited direct current (SEDC) motor configuration is the ability to produce high starting torque at low operating speeds. This chapter presents a sensorless (i.e., the approach only requires current measurements) control method for velocity tracking control of the SEDC motor. It provides a mathematical model describing the rotor velocity dynamics of the SEDC motor turning an inertial load. The chapter formulates the observation error dynamics for the rotor velocity observer. A non-negative function is then used to illustrate that the observation error goes to zero exponentially fast when used in open-loop operation (i.e., the observed velocity). A voltage input controller which utilizes this observed velocity is designed in a stable, closed-loop fashion. The chapter analyzes the performance of the composite observer-controller error systems. Hardware is used to implement the sensorless velocity controller, however, only the current sensors are used to provide sensory information to the input voltage control algorithm.
