Método de controle Sensorless para motores síncronos de imãs permanentes

Abstract

This paper presents the study and development of a sensorless control method for the Permanent Magnet Synchronous Motor (PMSM) based on the estimation of back Electromotive Force (back-EMF). A vector control method is proposed to achieve speed regulation of Permanent Magnet Synchronous Motor. A speed observer is developed, based on the Backstepping (BS) technique, in order to estimate the rotor speed and the back Electromotive Force of the machine, thus eliminating the need for mechanical sensors to control the machine. A Proportional Integral controller (PI controller) is used to control the external speed loop. Besides this controller, another two Proportional Integral controllers are used to control the internal current loop. To ensure a safety start of the Permanent Magnet Synchronous Motor and a smooth transition to the vector control method, which is only reliable in medium and high speeds, this paper proposes a starting method based on I-f control. This control method works with speed open-loop and current closed-loop, allowing the speed regulation in low speed range and transiting to the vector control method after a predetermined speed value. Simulation results are presented in order to validate the control system with both methods, the I-f control and the vector control.