Encoder-less speed control of PMSM drive using adaptive observer

This paper mainly focuses on the full order state observer for the vector control (field-oriented control) of a surface mounted Permanent Magnet Synchronous Motor (PMSM) without the use of a speed sensor. Space Vector Pulse Width Modulation (SVPWM) technique has been used to generate three phase voltages from the dc link source. The inverter switches are designed here with no dead time compensation. The rotor speed is treated as an unknown parameter and the adaptation law for driving the estimated rotor speed is being carried out by the use of Popov's Hyper stability criteria. The proposed observer and the whole other system except the PWM generation block and the PMSM has been discretized i.e., the whole system is running at a variable sampling rate and rate transitions blocks have been used to make the bridges between the continuous and discrete subsystems. For making the observer to become dynamically faster the observer poles are fixed proportionally to its motor poles using pole placement technique. The whole system is being verified using MATLAB/Simulink environment.