Abstract:
This paper presents a position-sensorless vector
torque controller designed to achieve maximum efficiency over a
range of power and rotational speed for a synchronous reluctance
machine. A model of the synchronous reluctance machine is
presented which incorporates both winding and core losses. It is
then shown that a stator-flux-oriented control scheme can achieve
synchronous operation of the machine without a position sensor
at medium and high electrical frequencies. For a given speed and
torque, power losses in the machine are shown to be a function of
only the stator flux magnitude. As the power losses are a convex
function of the stator flux level, the optimal flux value can be
found using a one-dimensional optimization algorithm, such as
the Method of Sequential Quadratic Interpolations. Optimal flux
values for a synchronous reluctance machine are determined using
an experimental setup that accurately determines losses in the
motor/drive system. Experimental results obtained from the test
setup confirm the validity of the controller and the optimization
algorithm.
