LMI-Based Sensorless Control of Permanent-Magnet Synchronous Motors

A sensorless speed tracking control scheme for permanent-magnet synchronous motors (PMSMs) is presented in this paper. This efficient scheme provides the exponential convergence on estimation errors of rotor´s speed and position, and tracking error of rotor´s speed. First, the Takagi-Sugeno fuzzy model is used to represent the nonlinear system of PMSMs. Then, a state observer is constructed to estimate the rotor´s speed and position in the manner of exponentially convergent rate. For converting the tracking control into a stabilization problem, a new and novel control design called virtual-desired variable synthesis is proposed to define the internal desired states. Consequently, the practical controller is derived under some adequate assumptions; meanwhile, the feedback gains and the observer gains are obtained separately by solving a set of linear matrix inequalities pertaining to system stability. The performance of the proposed sensorless algorithm is verified by experiments of PMSMs for speed tracking.